{"id":19836498,"url":"https://github.com/guobinhit/myleetcode","last_synced_at":"2026-03-15T23:02:12.808Z","repository":{"id":39375322,"uuid":"145631771","full_name":"guobinhit/myleetcode","owner":"guobinhit","description":" ♨️ Detailed Java \u0026 Go \u0026 Python solution of LeetCode.","archived":false,"fork":false,"pushed_at":"2023-01-09T03:36:45.000Z","size":1461,"stargazers_count":52,"open_issues_count":0,"forks_count":35,"subscribers_count":4,"default_branch":"master","last_synced_at":"2025-04-06T16:48:46.917Z","etag":null,"topics":["algorithm","interview","leetcode","list","queue","search","sort","stack","string","tree"],"latest_commit_sha":null,"homepage":"https://guobinhit.github.io/myleetcode/","language":"Java","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/guobinhit.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":"CONTRIBUTING.md","funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2018-08-21T23:49:58.000Z","updated_at":"2024-11-27T06:02:08.000Z","dependencies_parsed_at":"2023-02-08T08:46:34.776Z","dependency_job_id":null,"html_url":"https://github.com/guobinhit/myleetcode","commit_stats":null,"previous_names":[],"tags_count":2,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/guobinhit%2Fmyleetcode","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/guobinhit%2Fmyleetcode/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/guobinhit%2Fmyleetcode/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/guobinhit%2Fmyleetcode/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/guobinhit","download_url":"https://codeload.github.com/guobinhit/myleetcode/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":251924544,"owners_count":21665987,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["algorithm","interview","leetcode","list","queue","search","sort","stack","string","tree"],"created_at":"2024-11-12T12:11:31.408Z","updated_at":"2026-03-15T23:02:07.758Z","avatar_url":"https://github.com/guobinhit.png","language":"Java","funding_links":[],"categories":[],"sub_categories":[],"readme":"# myleetcode\n\n![author](https://img.shields.io/badge/author-chariesgavin-blueviolet.svg)![issues](https://img.shields.io/github/issues/guobinhit/myleetcode.svg)![stars](https://img.shields.io/github/stars/guobinhit/myleetcode.svg)![forks](\thttps://img.shields.io/github/forks/guobinhit/myleetcode.svg)![license](https://img.shields.io/github/license/guobinhit/myleetcode.svg)\n\nMy LeetCode Solutions!\n\n## Contributing\n\nContributions are very welcome!\n\nIf you see an problem that you'd like to see fixed, the best way to make it happen is to help out by submitting a pull request implementing it. Refer to the [CONTRIBUTING.md](https://github.com/guobinhit/myleetcode/blob/master/CONTRIBUTING.md) file for more details about the workflow. \n\nYou can also ask for problem solving ideas and discuss in GitHub issues directly.\n\n\n## INDEX\n\n- **Learn**\n  - [Array and String](#array-and-string)\n  - [Queue \u0026 Stack](#queue--stack)\n  - [Linked List](#linked-list)\n  - [Hash Table](#hash-table)\n  - [Binary Search](#binary-search)\n  - [Binary Tree](#binary-tree)\n  - [Binary Search Tree](#binary-search-tree)\n  - [N-ary Tree](#n-ary-tree)\n  - [Trie (Prefix Tree)](#trie-prefix-tree)\n  - [Decision Tree](#decision-tree)\n  - [Recursion I](#recursion-i)\n  - [Recursion II](#recursion-ii)\n  - [Concurrency](#concurrency)\n  - [Others](#others)\n  - [Shell](#shell)\n  - [Database](#database)\n  - [Sort Algorithm](#sort-algorithm)\n  - [Search Algorithm](#search-algorithm)\n- **Interview**\n  - [Top Interview Questions](#top-interview-questions)\n    - [Easy Collection](#easy-collection)\n    - [Medium Collection](#medium-collection)\n    - [Hard Collection](#hard-collection)\n\n\n\n\n## Learn\n### Array and String\n\n|  #  |      Title     |   Solutions  |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_14.java) \u0026 Python|Easy| Introduction to String\n|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_26.java) \u0026 Python|Easy| Conclusion\n|27|[Remove Element](https://leetcode.com/problems/remove-element/)|[Java](../master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_27.java) \u0026 [Go](../master/codes/go/leetcodes/learn/array_and_string/27.go)|Easy| Two-Pointer Technique\n|28|[Implement strStr()](https://leetcode.com/problems/implement-strstr/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_28.java) \u0026 Python|Easy| Introduction to String\n|54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_54.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_54.py)|Medium| Introduction to 2D Array\n|66|[Plus One](https://leetcode.com/problems/plus-one/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_66.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_66.py)|Easy| Introduction to Array\n|67|[Add Binary](https://leetcode.com/problems/add-binary/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_67.java) \u0026 Python|Easy| Introduction to String\n|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_118.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_118.py)| Easy| Introduction to 2D Array\n|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_119.java) \u0026 Python| Easy| Conclusion\n|151|[Reverse Words in a String](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_151.java) \u0026 Python| Medium| Conclusion\n|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_167.java) \u0026 Python| Easy| Two-Pointer Technique\n|189|[Rotate Array](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_189.java) \u0026 Python| Easy| Conclusion\n|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_209.java) \u0026 Python| Medium| Two-Pointer Technique\n|283|[Move Zeroes](https://leetcode.com/problems/move-zeroes/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_283.java) \u0026 Python| Easy| Conclusion\n|344|[Reverse String](https://leetcode.com/problems/reverse-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_344.java) \u0026 Python| Easy| Two-Pointer Technique\n|485|[Max Consecutive Ones](https://leetcode.com/problems/diagonal-traverse/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_485.java) \u0026 Python |Easy| Two-Pointer Technique\n|498|[Diagonal Traverse](https://leetcode.com/problems/diagonal-traverse/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_498.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_498.py) |Medium| Introduction to 2D Array\n|557|[Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_557.java) \u0026 Python |Easy| Conclusion\n|561|[Array Partition I](https://leetcode.com/problems/array-partition-i/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_561.java)  \u0026 Python|Easy| Two-Pointer Technique\n|724|[Find Pivot Index](https://leetcode.com/problems/find-pivot-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_724.java)  \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_724.py)| Easy | Introduction to Array\n|747|[Largest Number Greater Than Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_747.java)  \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/array_and_string/_747.py)| Easy| Introduction to Array\n\n\n\n### Queue \u0026 Stack\n\n|  #  |      Title     |   Solutions   |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_20.java) \u0026 Python|Easy| Stack: Last-in-first-out Data Structure\n|133|[Clone Graph](https://leetcode.com/problems/clone-graph/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_133.java) \u0026 Python|Medium| Stack and DFS\n|150|[Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_150.java) \u0026 Python|Medium| Stack: Last-in-first-out Data Structure\n|155|[Min Stack](https://leetcode.com/problems/min-stack/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_155.java) \u0026 Python|Easy| Stack: Last-in-first-out Data Structure\n|200|[Number of Islands](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_200.java) \u0026 Python|Medium| Queue and BFS\n|225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_225.java) \u0026 Python|Easy| Conclusion\n|232|[Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_232.java) \u0026 Python|Easy| Conclusion\n|279|[Perfect Squares](https://leetcode.com/problems/perfect-squares/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_279.java) \u0026 Python|Medium| Queue and BFS\n|394|[Decode String](https://leetcode.com/problems/decode-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_394.java) \u0026 Python|Medium| Conclusion\n|494|[Target Sum](https://leetcode.com/problems/target-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_494.java) \u0026 Python|Medium| Stack and DFS\n|542|[01 Matrix](https://leetcode.com/problems/01-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_542.java) \u0026 Python|Medium| Conclusion\n|622|[Design Circular Queue](https://leetcode.com/problems/longest-common-prefix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_622.java) \u0026 Python|Medium| Queue: First-in-first-out Data Structure\n|733|[Flood Fill](https://leetcode.com/problems/flood-fill/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_733.java) \u0026 Python|Easy| Conclusion\n|739|[Daily Temperatures](https://leetcode.com/problems/daily-temperatures/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_739.java) \u0026 Python|Medium| Stack: Last-in-first-out Data Structure\n|752|[Open the Lock](https://leetcode.com/problems/open-the-lock/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_752.java) \u0026 Python|Medium| Queue and BFS\n|841|[Keys and Rooms](https://leetcode.com/problems/keys-and-rooms/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/queue_stack/_841.java) \u0026 Python|Medium| Conclusion\n\n\n\n### Linked List\n\n|  #  |      Title     |   Solutions  |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_2.java) \u0026 Python|Medium| Conclusion\n|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_19.java) \u0026 Python|Medium| Two Pointer Technique\n|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_21.java) \u0026 Python|Easy| Conclusion\n|61|[Rotate List](https://leetcode.com/problems/rotate-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_61.java) \u0026 Python|Medium| Conclusion\n|135|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_135.java) \u0026 Python|Medium| Conclusion\n|141|[Linked List Cycle](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_141.java) \u0026 Python|Easy| Two Pointer Technique\n|142|[Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_142.java) \u0026 Python|Medium| Two Pointer Technique\n|160|[Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_160.java) \u0026 Python|Easy| Two Pointer Technique\n|203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_203.java) \u0026 Python|Easy| Classic Problems\n|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_206.java) \u0026 Python|Easy| Classic Problems\n|234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_234.java) \u0026 Python|Easy| Classic Problems\n|328|[Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_328.java) \u0026 Python|Medium| Classic Problems\n|430|[Flatten a Multilevel Doubly Linked List](https://leetcode.com/problems/flatten-a-multilevel-doubly-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_430.java) \u0026 Python|Medium| Conclusion\n|707|[Design Linked List](https://leetcode.com/problems/number-of-islands/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_707.java) \u0026 Python|Easy| Singly Linked List\n\n\n\n### Hash Table\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|1|[Two Sum](https://leetcode.com/problems/two-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_1.java) \u0026 Python |Easy| Practical Application - Hash Map\n|3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_3.java) \u0026 Python |Medium| Conclusion\n|36|[Valid Sudoku](https://leetcode.com/problems/valid-sudoku/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_36.java) \u0026 Python |Medium| Practical Application - Design the Key\n|49|[Group Anagrams](https://leetcode.com/problems/group-anagrams/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_49.java) \u0026 Python |Medium| Practical Application - Design the Key\n|136|[Single Number](https://leetcode.com/problems/single-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_136.java) \u0026 Python |Easy| Practical Application - Hash Set\n|202|[Happy Number](https://leetcode.com/problems/happy-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_202.java) \u0026 Python |Easy| Practical Application - Hash Set\n|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_205.java) \u0026 Python |Easy| Practical Application - Hash Map\n|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_217.java) \u0026 Python |Easy| Practical Application - Hash Set\n|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_219.java) \u0026 Python |Easy| Practical Application - Hash Map\n|347|[Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_347.java) \u0026 Python |Medium| Conclusion\n|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_349.java) \u0026 Python |Easy| Practical Application - Hash Set\n|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_350.java) \u0026 Python |Easy| Practical Application - Hash Map\n|380|[Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_380.java) \u0026 Python |Medium| Conclusion\n|387|[First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_387.java) \u0026 Python |Easy| Practical Application - Hash Map\n|454|[4Sum II](https://leetcode.com/problems/4sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_454.java) \u0026 Python |Medium| Conclusion\n|599|[Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_599.java) \u0026 Python |Easy| Practical Application - Hash Map\n|652|[Find Duplicate Subtrees](https://leetcode.com/problems/find-duplicate-subtrees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_652.java) \u0026 Python |Medium| Practical Application - Design the Key\n|705|[Design HashSet](https://leetcode.com/problems/design-hashset/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_705.java) \u0026 Python |Easy| Design a Hash Table\n|706|[Design HashMap](https://leetcode.com/problems/design-hashmap/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_706.java) \u0026 Python |Easy| Design a Hash Table\n|771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/hash_table/_771.java) \u0026 Python |Easy| Conclusion\n\n\n### Binary Search\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|4|[Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_4.java) \u0026 Python |Hard| More Practices II\n|33|[Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_33.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_33.py)|Medium| Template I\n|34|[Find First and Last Position of Element in Sorted Array](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_34.java) \u0026 Python |Medium| Template III\n|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_50.java) \u0026 Python |Medium| Conclusion\n|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_69.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_69.py)|Easy| Template I\n|153|[Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_153.java) \u0026 Python|Medium| Template II\n|154|[Find Minimum in Rotated Sorted Array II](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_154.java) \u0026 Python| Hard| More Practices\n|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_162.java) \u0026 Python|Medium| Template II\n|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_167.java) \u0026 Python |Easy| More Practices\n|278|[First Bad Version](https://leetcode.com/problems/first-bad-version/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_278.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_278.py)|Easy| Template II\n|287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_287.java) \u0026 Python |Medium| More Practices II\n|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_349.java) \u0026 Python |Easy| More Practices\n|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_350.java) \u0026 Python |Easy| More Practices\n|367|[Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_367.java) \u0026 Python |Easy| Conclusion\n|374|[Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_374.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_374.py)|Easy| Template I\n|410|[Split Array Largest Sum](https://leetcode.com/problems/split-array-largest-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_410.java) \u0026 Python |Hard| More Practices II\n|658|[Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_658.java) \u0026 Python |Medium| Template III\n|704|[Binary Search](https://leetcode.com/problems/binary-search/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_704.java) \u0026 [Python](https://github.com/guobinhit/myleetcode/blob/master/codes/python/leetcodes/src/main/python/com/hit/basmath/learn/binary_search/_704.py)|Easy| Background\n|719|[Find K-th Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_719.java) \u0026 Python |Hard| More Practices II\n|744|[Find Smallest Letter Greater Than Target](https://leetcode.com/problems/find-smallest-letter-greater-than-target/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_744.java) \u0026 Python|Easy| Conclusion\n\n\n\n### Binary Tree\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|94|[Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_94.java) \u0026 Python |Medium| Traverse A Tree\n|101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_101.java) \u0026 Python |Easy| Solve Tree Problems Recursively\n|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_102.java) \u0026 Python |Medium| Traverse A Tree\n|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_104.java) \u0026 Python |Easy| Solve Tree Problems Recursively\n|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_105.java) \u0026 Python |Medium| Conclusion\n|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_106.java) \u0026 Python |Medium| Conclusion\n|112|[Path Sum](https://leetcode.com/problems/path-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_112.java) \u0026 Python |Easy| Solve Tree Problems Recursively\n|116|[Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_116.java) \u0026 Python |Medium| Conclusion\n|117|[Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_117.java) \u0026 Python |Medium| Conclusion\n|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_144.java) \u0026 Python |Medium| Traverse A Tree\n|145|[Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_145.java) \u0026 Python |Hard| Traverse A Tree\n|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_236.java) \u0026 Python |Medium| Conclusion\n|297|[Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_297.java) \u0026 Python |Medium| Conclusion\n\n\n\n### Binary Search Tree\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_98.java) \u0026 Python |Medium| Introduction to BST\n|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_108.java) \u0026 Python |Easy| Appendix: Height-balanced BST\n|110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_110.java) \u0026 Python |Easy| Appendix: Height-balanced BST\n|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_173.java) \u0026 Python |Medium| Introduction to BST\n|220|[Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_220.java) \u0026 Python |Medium| Conclusion\n|235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_235.java) \u0026 Python |Easy| Conclusion\n|450|[Delete Node in a BST](https://leetcode.com/problems/delete-node-in-a-bst/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_450.java) \u0026 Python |Medium| Basic Operations in BST\n|700|[Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_700.java) \u0026 Python |Easy| Basic Operations in BST\n|701|[Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_701.java) \u0026 Python |Medium| Basic Operations in BST\n|703|[Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_703.java) \u0026 Python |Easy| Conclusion\n\n\n\n### N-ary Tree\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|429|[N-ary Tree Level Order Traversal](https://leetcode.com/problems/n-ary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_429.java) \u0026 Python |Easy| Traversal\n|559|[Maximum Depth of N-ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_559.java) \u0026 Python |Easy| Recursion\n|589|[N-ary Tree Preorder Traversal](https://leetcode.com/problems/n-ary-tree-preorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_589.java) \u0026 Python |Easy| Traversal\n|590|[N-ary Tree Postorder Traversal](https://leetcode.com/problems/n-ary-tree-postorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/n_ary_tree/_590.java) \u0026 Python |Easy| Traversal\n\n\n\n### Trie (Prefix Tree)\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_208.java) \u0026 Python |Medium| Basic Operations\n|211|[Add and Search Word - Data structure design](https://leetcode.com/problems/add-and-search-word-data-structure-design/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_211.java) \u0026 Python |Medium| Practical Application I\n|212|[Word Search II](https://leetcode.com/problems/word-search-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_212.java) \u0026 Python |Hard| Practical Application II\n|336|[Palindrome Pairs](https://leetcode.com/problems/palindrome-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_336.java) \u0026 Python |Hard| Practical Application II\n|421|[Maximum XOR of Two Numbers in an Array](https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_421.java) \u0026 Python |Medium| Practical Application II\n|648|[Replace Words](https://leetcode.com/problems/replace-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_648.java) \u0026 Python |Medium| Practical Application I\n|677|[Map Sum Pairs](https://leetcode.com/problems/map-sum-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/trie/_677.java) \u0026 Python |Medium| Practical Application I\n\n\n\n### Decision Tree\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n| ### |[Calculate Entropy](https://leetcode.com/explore/learn/card/decision-tree/285/implementation/2650/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/decision_tree/CalculateEntropy.java) \u0026 Python |Easy| Implementation\n| ### |[Calculate Maximum Information Gain](https://leetcode.com/explore/learn/card/decision-tree/285/implementation/2651/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/decision_tree/CalculateMaxInfoGain.java) \u0026 Python |Easy| Implementation\n\n\n\n### Recursion I\n\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_21.java) \u0026 Python|Easy| Conclusion\n|24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_i/_24.java) \u0026 Python| Medium| Principle of Recursion\n|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search/_50.java) \u0026 Python |Medium| Complexity Analysis\n|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_70.java) \u0026 Python| Easy| Memoization\n|95|[Unique Binary Search Trees II](https://leetcode.com/problems/unique-binary-search-trees-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_95.java) \u0026 Python|Medium| Conclusion\n|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_104.java) \u0026 Python |Easy| Complexity Analysis\n|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_118.java) \u0026 Python| Easy| Recurrence Relation\n|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_119.java) \u0026 Python| Easy| Recurrence Relation\n|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_206.java) \u0026 Python|Easy| Recurrence Relation\n|344|[Reverse String](https://leetcode.com/problems/reverse-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_344.java) \u0026 Python| Easy| Principle of Recursion\n|509|[Fibonacci Number](https://leetcode.com/problems/fibonacci-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/array_and_string/_509.java) \u0026 Python| Easy| Memoization\n|779|[K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/linked_list/_779.java) \u0026 Python|Medium| Conclusion\n\n\n\n### Recursion II\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|17|[Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_17.java) \u0026 Python |Medium| Conclusion\n|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_22.java) \u0026 Python |Medium| Recursion to Iteration\n|37|[Sudoku Solver](https://leetcode.com/problems/sudoku-solver/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_37.java) \u0026 Python |Hard| Backtracking\n|46|[Permutations](https://leetcode.com/problems/permutations/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_46.java) \u0026 Python |Medium| Conclusion\n|52|[N-Queens II](https://leetcode.com/problems/n-queens-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_52.java) \u0026 Python |Hard| Backtracking\n|77|[Combinations](https://leetcode.com/problems/combinations/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_77.java) \u0026 Python |Medium| Backtracking\n|84|[Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_84.java) \u0026 Python |Hard| Conclusion\n|94|[Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_94.java) \u0026 Python |Medium| Recursion to Iteration\n|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_search_tree/_98.java) \u0026 Python |Medium| Divide and Conquer\n|100|[Same Tree](https://leetcode.com/problems/same-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_100.java) \u0026 Python |Easy| Recursion to Iteration\n|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/binary_tree/_102.java) \u0026 Python |Medium| Recursion to Iteration\n|218|[The Skyline Problem](https://leetcode.com/problems/the-skyline-problem/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_218.java) \u0026 Python |Hard| Conclusion\n|240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_240.java) \u0026 Python |Medium| Divide and Conquer\n|912|[Sort an Array](https://leetcode.com/problems/sort-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/recursion_ii/_912.java) \u0026 Python|Medium| Divide and Conquer\n\n\n\n### Concurrency\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|1114|[Print in Order](https://leetcode.com/problems/print-in-order/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1114.java) \u0026 Python |Easy| Concurrency\n|1115|[Print FooBar Alternately](https://leetcode.com/problems/print-foobar-alternately/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1115.java) \u0026 Python |Medium| Concurrency\n|1116|[Print Zero Even Odd](https://leetcode.com/problems/print-zero-even-odd/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1116.java) \u0026 Python |Medium| Concurrency\n|1117|[Building H2O](https://leetcode.com/problems/building-h2o/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1117.java) \u0026 Python |Medium| Concurrency\n|1195|[Fizz Buzz Multithreaded](https://leetcode.com/problems/fizz-buzz-multithreaded/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1195.java) \u0026 Python |Medium| Concurrency\n|1226|[The Dining Philosophers](https://leetcode.com/problems/the-dining-philosophers/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/concurrency/_1226.java) \u0026 Python |Medium| Concurrency\n\n\n\n### Others\n\n|  #  |      Title     |   Solutions    |   Difficulty  | Tag                   \n|-----|----------------|:---------------:|:--------:|:-------------:\n|6|[ZigZag Conversion](https://leetcode.com/problems/zigzag-conversion/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_6.java) \u0026 Python |Medium| Others\n|9|[Palindrome Number](https://leetcode.com/problems/palindrome-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_9.java) \u0026 Python |Easy| Others\n|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_12.java) \u0026 Python |Medium| Others\n|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_16.java) \u0026 Python |Medium| Others\n|18|[4Sum](https://leetcode.com/problems/4sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_18.java) \u0026 Python |Medium| Others\n|25|[Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_25.java) \u0026 Python |Hard| Others\n|30|[Substring with Concatenation of All Words](https://leetcode.com/problems/substring-with-concatenation-of-all-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_30.java) \u0026 Python |Hard| Others\n|31|[Next Permutation](https://leetcode.com/problems/next-permutation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_31.java) \u0026 Python |Medium| Others\n|32|[Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_32.java) \u0026 Python |Hard| Others\n|35|[Search Insert Position](https://leetcode.com/problems/search-insert-position/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_35.java) \u0026 Python |Easy| Others\n|39|[Combination Sum](https://leetcode.com/problems/combination-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_39.java) \u0026 Python |Medium| Others\n|40|[Combination Sum II](https://leetcode.com/problems/combination-sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_40.java) \u0026 Python |Medium| Others\n|43|[Multiply Strings](https://leetcode.com/problems/multiply-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_43.java) \u0026 Python |Medium| Others\n|45|[Jump Game II](https://leetcode.com/problems/jump-game-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_45.java) \u0026 Python |Hard| Others\n|47|[Permutations II](https://leetcode.com/problems/permutations-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_47.java) \u0026 Python |Medium| Others\n|51|[N-Queens](https://leetcode.com/problems/n-queens/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_51.java) \u0026 Python |Hard| Others\n|57|[Insert Interval](https://leetcode.com/problems/insert-interval/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_57.java) \u0026 Python |Hard| Others\n|58|[Length of Last Word](https://leetcode.com/problems/length-of-last-word/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_58.java) \u0026 Python |Easy| Others\n|59|[Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_59.java) \u0026 Python |Medium| Others\n|60|[Permutation Sequence](https://leetcode.com/problems/permutation-sequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_60.java) \u0026 Python |Medium| Others\n|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_63.java) \u0026 Python |Medium| Others\n|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_64.java) \u0026 Python |Medium| Others\n|65|[Valid Number](https://leetcode.com/problems/valid-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_65.java) \u0026 Python |Hard| Others\n|68|[Text Justification](https://leetcode.com/problems/text-justification/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_68.java) \u0026 Python |Hard| Others\n|71|[Simplify Path](https://leetcode.com/problems/simplify-path/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_71.java) \u0026 Python |Medium| Others\n|72|[Edit Distance](https://leetcode.com/problems/edit-distance/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_72.java) \u0026 Python |Hard| Others\n|74|[Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_74.java) \u0026 Python |Medium| Others\n|80|[Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_80.java) \u0026 Python |Medium| Others\n|81|[Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_81.java) \u0026 Python |Medium| Others\n|82|[Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_82.java) \u0026 Python |Medium| Others\n|83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_83.java) \u0026 Python |Easy| Others\n|85|[Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_85.java) \u0026 Python |Hard| Others\n|86|[Partition List](https://leetcode.com/problems/partition-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_86.java) \u0026 Python |Medium| Others\n|87|[Scramble String](https://leetcode.com/problems/scramble-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_87.java) \u0026 Python |Hard| Others\n|89|[Gray Code](https://leetcode.com/problems/gray-code/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_89.java) \u0026 Python |Medium| Others\n|90|[Subsets II](https://leetcode.com/problems/subsets-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_90.java) \u0026 Python |Medium| Others\n|92|[Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_92.java) \u0026 Python |Medium| Others\n|93|[Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_93.java) \u0026 Python |Medium| Others\n|96|[Unique Binary Search Trees](https://leetcode.com/problems/unique-binary-search-trees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_96.java) \u0026 Python |Medium| Others\n|97|[Interleaving String](https://leetcode.com/problems/interleaving-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_97.java) \u0026 Python |Hard| Others\n|99|[Recover Binary Search Tree](https://leetcode.com/problems/recover-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_99.java) \u0026 Python |Hard| Others\n|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_107.java) \u0026 Python |Easy| Others\n|109|[Convert Sorted List to Binary Search Tree](https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_109.java) \u0026 Python |Medium| Others\n|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_111.java) \u0026 Python |Easy| Others\n|113|[Path Sum II](https://leetcode.com/problems/path-sum-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_113.java) \u0026 Python |Medium| Others\n|114|[Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_114.java) \u0026 Python |Medium| Others\n|115|[Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_115.java) \u0026 Python |Hard| Others\n|120|[Triangle](https://leetcode.com/problems/triangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_120.java) \u0026 Python |Medium| Others\n|123|[Best Time to Buy and Sell Stock III](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_123.java) \u0026 Python |Hard| Others\n|126|[Word Ladder II](https://leetcode.com/problems/word-ladder-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_126.java) \u0026 Python |Hard| Others\n|129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_129.java) \u0026 Python |Medium| Others\n|132|[Palindrome Partitioning II](https://leetcode.com/problems/palindrome-partitioning-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_132.java) \u0026 Python |Hard| Others\n|134|[Gas Station](https://leetcode.com/problems/gas-station/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_134.java) \u0026 Python |Medium| Others\n|135|[Candy](https://leetcode.com/problems/candy/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_135.java) \u0026 Python |Hard| Others\n|137|[Single Number II](https://leetcode.com/problems/single-number-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_137.java) \u0026 Python |Medium| Others\n|143|[Reorder List](https://leetcode.com/problems/reorder-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_143.java) \u0026 Python |Medium| Others\n|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_147.java) \u0026 Python |Medium| Others\n|164|[Maximum Gap](https://leetcode.com/problems/maximum-gap/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_164.java) \u0026 Python |Hard| Others\n|165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_165.java) \u0026 Python |Medium| Others\n|168|[Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_168.java) \u0026 Python |Easy| Others\n|174|[Dungeon Game](https://leetcode.com/problems/dungeon-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_174.java) \u0026 Python |Hard| Others\n|187|[Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_187.java) \u0026 Python |Medium| Others\n|188|[Best Time to Buy and Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_188.java) \u0026 Python |Hard| Others\n|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_199.java) \u0026 Python |Medium| Others\n|201|[Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_201.java) \u0026 Python |Medium| Others\n|213|[House Robber II](https://leetcode.com/problems/house-robber-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_213.java) \u0026 Python |Medium| Others\n|214|[Shortest Palindrome](https://leetcode.com/problems/shortest-palindrome/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_214.java) \u0026 Python |Hard| Others\n|216|[Combination Sum III](https://leetcode.com/problems/combination-sum-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_216.java) \u0026 Python |Medium| Others\n|221|[Maximal Square](https://leetcode.com/problems/maximal-square/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_221.java) \u0026 Python |Medium| Others\n|222|[Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_222.java) \u0026 Python |Medium| Others\n|223|[Rectangle Area](https://leetcode.com/problems/rectangle-area/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_223.java) \u0026 Python |Medium| Others\n|224|[Basic Calculator](https://leetcode.com/problems/basic-calculator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_224.java) \u0026 Python |Hard| Others\n|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_226.java) \u0026 Python |Easy| Others\n|228|[Summary Ranges](https://leetcode.com/problems/summary-ranges/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_228.java) \u0026 Python |Medium| Others\n|229|[Majority Element II](https://leetcode.com/problems/majority-element-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_229.java) \u0026 Python |Medium| Others\n|231|[Power of Two](https://leetcode.com/problems/power-of-two/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_231.java) \u0026 Python |Easy| Others\n|233|[Number of Digit One](https://leetcode.com/problems/number-of-digit-one/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_233.java) \u0026 Python |Hard| Others\n|241|[Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_241.java) \u0026 Python |Medium| Others\n|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_257.java) \u0026 Python |Easy| Others\n|258|[Add Digits](https://leetcode.com/problems/add-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_258.java) \u0026 Python |Easy| Others\n|260|[Single Number III](https://leetcode.com/problems/single-number-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_260.java) \u0026 Python |Medium| Others\n|263|[Ugly Number](https://leetcode.com/problems/ugly-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_263.java) \u0026 Python |Easy| Others\n|264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_264.java) \u0026 Python |Medium| Others\n|273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_273.java) \u0026 Python |Hard| Others\n|274|[H-Index](https://leetcode.com/problems/h-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_274.java) \u0026 Python |Medium| Others\n|275|[H-Index II](https://leetcode.com/problems/h-index-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_275.java) \u0026 Python |Medium| Others\n|282|[Expression Add Operators](https://leetcode.com/problems/expression-add-operators/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_282.java) \u0026 Python |Hard| Others\n|284|[Peeking Iterator](https://leetcode.com/problems/peeking-iterator/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_284.java) \u0026 Python |Medium| Others\n|290|[Word Pattern](https://leetcode.com/problems/word-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_290.java) \u0026 Python |Easy| Others\n|292|[Nim Game](https://leetcode.com/problems/nim-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_292.java) \u0026 Python |Easy| Others\n|299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_299.java) \u0026 Python |Easy| Others\n|303|[Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_303.java) \u0026 Python |Easy| Others\n|304|[Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_304.java) \u0026 Python |Medium| Others\n|306|[Additive Number](https://leetcode.com/problems/additive-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_306.java) \u0026 Python |Medium| Others\n|307|[Range Sum Query - Mutable](https://leetcode.com/problems/range-sum-query-mutable/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_307.java) \u0026 Python |Medium| Others\n|310|[Minimum Height Trees](https://leetcode.com/problems/minimum-height-trees/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_310.java) \u0026 Python |Medium| Others\n|313|[Super Ugly Number](https://leetcode.com/problems/super-ugly-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_313.java) \u0026 Python |Medium| Others\n|316|[Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_316.java) \u0026 Python |Hard| Others\n|318|[Maximum Product of Word Lengths](https://leetcode.com/problems/maximum-product-of-word-lengths/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_318.java) \u0026 Python |Medium| Others\n|319|[Bulb Switcher](https://leetcode.com/problems/bulb-switcher/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_319.java) \u0026 Python |Medium| Others\n|321|[Create Maximum Number](https://leetcode.com/problems/create-maximum-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_321.java) \u0026 Python |Hard| Others\n|327|[Count of Range Sum](https://leetcode.com/problems/count-of-range-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_327.java) \u0026 Python |Hard| Others\n|330|[Patching Array](https://leetcode.com/problems/patching-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_330.java) \u0026 Python |Hard| Others\n|331|[Verify Preorder Serialization of a Binary Tree](https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_331.java) \u0026 Python |Medium| Others\n|332|[Reconstruct Itinerary](https://leetcode.com/problems/reconstruct-itinerary/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_332.java) \u0026 Python |Medium| Others\n|335|[Self Crossing](https://leetcode.com/problems/self-crossing/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_335.java) \u0026 Python |Hard| Others\n|337|[House Robber III](https://leetcode.com/problems/house-robber-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_337.java) \u0026 Python |Medium| Others\n|338|[Counting Bits](https://leetcode.com/problems/counting-bits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_338.java) \u0026 Python |Medium| Others\n|342|[Power of Four](https://leetcode.com/problems/power-of-four/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_342.java) \u0026 Python |Easy| Others\n|343|[Integer Break](https://leetcode.com/problems/integer-break/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_343.java) \u0026 Python |Medium| Others\n|345|[Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_345.java) \u0026 Python |Easy| Others\n|352|[Data Stream as Disjoint Intervals](https://leetcode.com/problems/data-stream-as-disjoint-intervals/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_352.java) \u0026 Python |Hard| Others\n|354|[Russian Doll Envelopes](https://leetcode.com/problems/russian-doll-envelopes/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_354.java) \u0026 Python |Hard| Others\n|355|[Design Twitter](https://leetcode.com/problems/design-twitter/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_355.java) \u0026 Python |Medium| Others\n|357|[Count Numbers with Unique Digits](https://leetcode.com/problems/count-numbers-with-unique-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_357.java) \u0026 Python |Medium| Others\n|363|[Max Sum of Rectangle No Larger Than K](https://leetcode.com/problems/max-sum-of-rectangle-no-larger-than-k/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_363.java) \u0026 Python |Hard| Others\n|365|[Water and Jug Problem](https://leetcode.com/problems/water-and-jug-problem/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_365.java) \u0026 Python |Medium| Others\n|368|[Largest Divisible Subset](https://leetcode.com/problems/largest-divisible-subset/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_368.java) \u0026 Python |Medium| Others\n|372|[Super Pow](https://leetcode.com/problems/super-pow/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_372.java) \u0026 Python |Medium| Others\n|373|[Find K Pairs with Smallest Sums](https://leetcode.com/problems/find-k-pairs-with-smallest-sums/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_373.java) \u0026 Python |Medium| Others\n|375|[Guess Number Higher or Lower II](https://leetcode.com/problems/guess-number-higher-or-lower-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_375.java) \u0026 Python |Medium| Others\n|376|[Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_376.java) \u0026 Python |Medium| Others\n|377|[Combination Sum IV](https://leetcode.com/problems/combination-sum-iv/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_377.java) \u0026 Python |Medium| Others\n|381|[Insert Delete GetRandom O(1) - Duplicates allowed](https://leetcode.com/problems/insert-delete-getrandom-o1-duplicates-allowed/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_381.java) \u0026 Python |Hard| Others\n|382|[Linked List Random Node](https://leetcode.com/problems/linked-list-random-node/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_382.java) \u0026 Python |Medium| Others\n|383|[Ransom Note](https://leetcode.com/problems/ransom-note/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_383.java) \u0026 Python |Easy| Others\n|385|[Mini Parser](https://leetcode.com/problems/mini-parser/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_385.java) \u0026 Python |Medium| Others\n|386|[Lexicographical Numbers](https://leetcode.com/problems/lexicographical-numbers/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_386.java) \u0026 Python |Medium| Others\n|388|[Longest Absolute File Path](https://leetcode.com/problems/longest-absolute-file-path/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_388.java) \u0026 Python |Medium| Others\n|389|[Find the Difference](https://leetcode.com/problems/find-the-difference/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_389.java) \u0026 Python |Easy| Others\n|390|[Elimination Game](https://leetcode.com/problems/elimination-game/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_390.java) \u0026 Python |Medium| Others\n|391|[Perfect Rectangle](https://leetcode.com/problems/perfect-rectangle/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_391.java) \u0026 Python |Hard| Others\n|392|[Is Subsequence](https://leetcode.com/problems/is-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_392.java) \u0026 Python |Easy| Others\n|393|[UTF-8 Validation](https://leetcode.com/problems/utf-8-validation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_393.java) \u0026 Python |Medium| Others\n|395|[Longest Substring with At Least K Repeating Characters](https://leetcode.com/problems/longest-substring-with-at-least-k-repeating-characters/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_395.java) \u0026 Python |Medium| Others\n|396|[Rotate Function](https://leetcode.com/problems/rotate-function/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_396.java) \u0026 Python |Medium| Others\n|397|[Integer Replacement](https://leetcode.com/problems/integer-replacement/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_397.java) \u0026 Python |Medium| Others\n|398|[Random Pick Index](https://leetcode.com/problems/random-pick-index/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_398.java) \u0026 Python |Medium| Others\n|399|[Evaluate Division](https://leetcode.com/problems/evaluate-division/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_399.java) \u0026 Python |Medium| Others\n|400|[Nth Digit](https://leetcode.com/problems/nth-digit/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_400.java) \u0026 Python |Medium| Others\n|401|[Binary Watch](https://leetcode.com/problems/binary-watch/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_401.java) \u0026 Python |Easy| Others\n|402|[Remove K Digits](https://leetcode.com/problems/remove-k-digits/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_402.java) \u0026 Python |Medium| Others\n|403|[Frog Jump](https://leetcode.com/problems/frog-jump/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_403.java) \u0026 Python |Hard| Others\n|404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_404.java) \u0026 Python |Easy| Others\n|405|[Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_405.java) \u0026 Python |Easy| Others\n|407|[Trapping Rain Water II](https://leetcode.com/problems/trapping-rain-water-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_407.java) \u0026 Python |Hard| Others\n|409|[Longest Palindrome](https://leetcode.com/problems/longest-palindrome/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_409.java) \u0026 Python |Easy| Others\n|413|[Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_413.java) \u0026 Python |Medium| Others\n|414|[Third Maximum Number](https://leetcode.com/problems/third-maximum-number/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_414.java) \u0026 Python |Easy| Others\n|415|[Add Strings](https://leetcode.com/problems/add-strings/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_415.java) \u0026 Python |Easy| Others\n|416|[Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_416.java) \u0026 Python |Medium| Others\n|417|[Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_417.java) \u0026 Python |Medium| Others\n|419|[Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_419.java) \u0026 Python |Medium| Others\n|420|[Strong Password Checker](https://leetcode.com/problems/strong-password-checker/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_420.java) \u0026 Python |Hard| Others\n|423|[Reconstruct Original Digits from English](https://leetcode.com/problems/reconstruct-original-digits-from-english/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_423.java) \u0026 Python |Medium| Others\n|424|[Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_424.java) \u0026 Python |Medium| Others\n|427|[Construct Quad Tree](https://leetcode.com/problems/construct-quad-tree/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_427.java) \u0026 Python |Medium| Others\n|432|[All O\\`one Data Structure](https://leetcode.com/problems/all-oone-data-structure/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_432.java) \u0026 Python |Hard| Others\n|433|[Minimum Genetic Mutation](https://leetcode.com/problems/minimum-genetic-mutation/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_433.java) \u0026 Python |Medium| Others\n|434|[Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_434.java) \u0026 Python |Easy| Others\n|435|[Non-overlapping Intervals](https://leetcode.com/problems/non-overlapping-intervals/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_435.java) \u0026 Python |Medium| Others\n|436|[Find Right Interval](https://leetcode.com/problems/find-right-interval/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_436.java) \u0026 Python |Medium| Others\n|437|[Path Sum III](https://leetcode.com/problems/path-sum-iii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_437.java) \u0026 Python |Easy| Others\n|438|[Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_438.java) \u0026 Python |Medium| Others\n|440|[K-th Smallest in Lexicographical Order](https://leetcode.com/problems/k-th-smallest-in-lexicographical-order/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_440.java) \u0026 Python |Hard| Others\n|441|[Arranging Coins](https://leetcode.com/problems/arranging-coins/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_441.java) \u0026 Python |Easy| Others\n|442|[Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_442.java) \u0026 Python |Medium| Others\n|443|[String Compression](https://leetcode.com/problems/string-compression/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_443.java) \u0026 Python |Easy| Others\n|445|[Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_445.java) \u0026 Python |Medium| Others\n|446|[Arithmetic Slices II - Subsequence](https://leetcode.com/problems/arithmetic-slices-ii-subsequence/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_446.java) \u0026 Python |Hard| Others\n|447|[Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_447.java) \u0026 Python |Easy| Others\n|448|[Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_448.java) \u0026 Python |Easy| Others\n|449|[Serialize and Deserialize BST](https://leetcode.com/problems/serialize-and-deserialize-bst/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_449.java) \u0026 Python |Medium| Others\n|451|[Sort Characters By Frequency](https://leetcode.com/problems/sort-characters-by-frequency/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_451.java) \u0026 Python |Medium| Others\n|452|[Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_452.java) \u0026 Python |Medium| Others\n|453|[Minimum Moves to Equal Array Elements](https://leetcode.com/problems/minimum-moves-to-equal-array-elements/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_453.java) \u0026 Python |Easy| Others\n|455|[Assign Cookies](https://leetcode.com/problems/assign-cookies/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_455.java) \u0026 Python |Easy| Others\n|456|[132 Pattern](https://leetcode.com/problems/132-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_456.java) \u0026 Python |Medium| Others\n|457|[Circular Array Loop](https://leetcode.com/problems/circular-array-loop/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_457.java) \u0026 Python |Medium| Others\n|458|[Poor Pigs](https://leetcode.com/problems/poor-pigs/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_458.java) \u0026 Python |Hard| Others\n|459|[Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_459.java) \u0026 Python |Easy| Others\n|460|[LFU Cache](https://leetcode.com/problems/lfu-cache/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_460.java) \u0026 Python |Hard| Others\n|462|[Minimum Moves to Equal Array Elements II](https://leetcode.com/problems/minimum-moves-to-equal-array-elements-ii/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_462.java) \u0026 Python |Medium| Others\n|463|[Island Perimeter](https://leetcode.com/problems/island-perimeter/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_463.java) \u0026 Python |Easy| Others\n|464|[Can I Win](https://leetcode.com/problems/can-i-win/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_464.java) \u0026 Python |Medium| Others\n|466|[Count The Repetitions](https://leetcode.com/problems/count-the-repetitions/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_466.java) \u0026 Python |Hard| Others\n|467|[Unique Substrings in Wraparound String](https://leetcode.com/problems/unique-substrings-in-wraparound-string/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_467.java) \u0026 Python |Medium| Others\n|468|[Validate IP Address](https://leetcode.com/problems/validate-ip-address/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_468.java) \u0026 Python |Medium| Others\n|470|[Implement Rand10() Using Rand7()](https://leetcode.com/problems/implement-rand10-using-rand7/description/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_470.java) \u0026 Python |Medium| Others\n|472|[Concatenated Words](https://leetcode.com/problems/concatenated-words/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_472.java) \u0026 Python |Hard| Others\n|473|[Matchsticks to Square](https://leetcode.com/problems/matchsticks-to-square/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_473.java) \u0026 Python |Medium| Others\n|474|[Ones and Zeroes](https://leetcode.com/problems/ones-and-zeroes/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_474.java) \u0026 Python |Medium| Others\n|475|[Heaters](https://leetcode.com/problems/heaters/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_475.java) \u0026 Python |Easy| Others\n|476|[Number Complement](https://leetcode.com/problems/number-complement/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_476.java) \u0026 Python |Easy| Others\n|477|[Total Hamming Distance](https://leetcode.com/problems/total-hamming-distance/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_477.java) \u0026 Python |Medium| Others\n|478|[Generate Random Point in a Circle](https://leetcode.com/problems/generate-random-point-in-a-circle/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_478.java) \u0026 Python |Medium| Others\n|479|[Largest Palindrome Product](https://leetcode.com/problems/largest-palindrome-product/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_479.java) \u0026 Python |Hard| Others\n|480|[Sliding Window Median](https://leetcode.com/problems/sliding-window-median/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_480.java) \u0026 Python |Hard| Others\n|481|[Magical String](https://leetcode.com/problems/magical-string/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_481.java) \u0026 Python |Medium| Others\n|482|[License Key Formatting](https://leetcode.com/problems/license-key-formatting/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_482.java) \u0026 Python |Easy| Others\n|483|[Smallest Good Base](https://leetcode.com/problems/smallest-good-base/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_483.java) \u0026 Python |Hard| Others\n|486|[Predict the Winner](https://leetcode.com/problems/predict-the-winner/)|[Java](https://github.com/guobinhit/myleetcode/blob/master/codes/java/leetcodes/src/main/java/com/hit/basmath/learn/others/_486.java) \u0026 Python |Medium| Others\n|488|[Zuma Game](https://leetcode.com/problems/zuma-game/)|[Java](https://github.com/guobinh","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fguobinhit%2Fmyleetcode","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fguobinhit%2Fmyleetcode","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fguobinhit%2Fmyleetcode/lists"}