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https://github.com/lucasbotang/leetcode

My solutions for LeetCode
https://github.com/lucasbotang/leetcode
algorithm-challenges algorithms leetcode python sql
Last synced: about 1 month ago
JSON representation
My solutions for LeetCode
Host: GitHub
URL: https://github.com/lucasbotang/leetcode
Owner: LucasBoTang
License: mit
Created: 2018-02-19T23:54:31.000Z (almost 7 years ago)
Default Branch: master
Last Pushed: 2024-01-16T07:58:48.000Z (12 months ago)
Last Synced: 2024-01-16T10:45:23.253Z (12 months ago)
Topics: algorithm-challenges, algorithms, leetcode, python, sql
Language: Python
Homepage:
Size: 354 KB
Stars: 7
Watchers: 1
Forks: 2
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project

README

        # LeetCode

My solutions for LeetCode:

|#|Title|Solution|Difficulty|

|-|-----|--------|----------|

|1|[Two Sum](https://leetcode.com/problems/two-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/001two_sum.py)|Easy|

|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/002add_two_numbers.py)|Medium|

|3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/003longest_substring_without_repeating_characters.py)|Medium|

|4|[Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/004median_of_two_sorted_arrays.py)|Hard|

|5|[Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/005longest_palindromic_substring.py)|Medium|

|6|[ZigZag Conversion](https://leetcode.com/problems/zigzag-conversion)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/006zigzag_conversion.py)|Medium|

|7|[Reverse Integer](https://leetcode.com/problems/reverse-integer)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/007reverse_integer.py)|Easy|

|8|[String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/008string_to_integer(atoi).py)|Medium|

|9|[Palindrome Number](https://leetcode.com/problems/palindrome-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/009palindrome_number.py)|Easy|

|11|[Container With Most Water](https://leetcode.com/problems/container-with-most-water)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/011container_with_most_water.py)|Medium|

|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/012integer_to_roman.py)|Medium|

|13|[Roman to Integer](https://leetcode.com/problems/roman-to-integer)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/013roman_to_integer.py)|Easy|

|14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/014longest_common_prefix.py)|Easy|

|15|[3Sum](https://leetcode.com/problems/3sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/015three_sum.py)|Medium|

|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/016three_sum_closest.py)|Medium|

|17|[Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/017letter_combinations_of_a_phone_number.py)|Medium|

|18|[4Sum](https://leetcode.com/problems/4sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/018four_sum.py)|Medium|

|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/019remove_nth_node_from_end_of_list.py)|Medium|

|20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/020valid_parentheses.py)|Easy|

|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/021merge_two_sorted_lists.py)|Easy|

|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/022generate_parentheses.py)|Medium|

|24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/024swap_nodes_in_pairs.py)|Medium|

|25|[Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/025reverse_nodes_in_k_group.py)|Hard|

|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/026remove_duplicates_from_sorted_array.py)|Easy|

|27|[Remove Element](https://leetcode.com/problems/remove-element)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/027remove_element.py)|Easy|

|28|[Implement strStr()](https://leetcode.com/problems/implement-strstr)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/028implement_strStr().py)|Easy|

|29|[Divide Two Integers](https://leetcode.com/problems/divide-two-integers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/029divide_two_integers.py)|Medium|

|31|[Next Permutation](https://leetcode.com/problems/next-permutation)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/031next_permutation.py)|Medium|

|33|[Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/033search_in_rotated_sorted_array.py)|Medium|

|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)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/034find_first_and_last_position_of_element_in_sorted_array.py)|Medium|

|35|[Search Insert Position](https://leetcode.com/problems/search-insert-position)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/035search_insert_position.py)|Easy|

|36|[Valid Sudoku](https://leetcode.com/problems/valid-sudoku)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/036valid_sudoku.py)|Medium|

|38|[Count and Say](https://leetcode.com/problems/count-and-say)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/038count_and_say.py)|Easy|

|39|[Combination Sum](https://leetcode.com/problems/combination-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/039combination_sum.py)|Medium|

|40|[Combination Sum II](https://leetcode.com/problems/combination-sum-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/040combination_sum2.py)|Medium|

|43|[Multiply Strings](https://leetcode.com/problems/multiply-strings)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/043multiply_strings.py)|Medium|

|46|[Permutations](https://leetcode.com/problems/permutations)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/046permutations.py)|Medium|

|47|[Permutations II](https://leetcode.com/problems/permutations-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/047permutations2.py)|Medium|

|48|[Rotate Image](https://leetcode.com/problems/rotate-image)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/048rotate_image.py)|Medium|

|49|[Group Anagrams](https://leetcode.com/problems/group-anagrams)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/049group_anagrams.py)|Medium|

|50|[Pow(x, n)](https://leetcode.com/problems/powx-n)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/050pow(x%2C%20n).py)|Medium|

|53|[Maximum Subarray](https://leetcode.com/problems/maximum-subarray)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/053maximum_subarray.py)|Easy|

|54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/054spiral_matrix.py)|Medium|

|55|[Jump Game](https://leetcode.com/problems/jump-game/)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/055jump_game.py)|Medium|

|56|[Merge Intervals](https://leetcode.com/problems/merge-intervals)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/056merge_intervals.py)|Medium|

|58|[Length of Last Word](https://leetcode.com/problems/length-of-last-word)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/058length_of_last_word.py)|Easy|

|59|[Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/059spiral_matrix2.py)|Medium|

|60|[Permutation Sequence](https://leetcode.com/problems/permutation-sequence)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/060permutation_sequence.py)|Medium|

|61|[Rotate List](https://leetcode.com/problems/rotate-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/061rotate_list.py)|Medium|

|62|[Unique Paths](https://leetcode.com/problems/unique-paths)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/062unique_paths.py)|Medium|

|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/063unique_paths2.py)|Medium|

|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/064minimum_path_sum.py)|Medium|

|66|[Plus One](https://leetcode.com/problems/plus-one)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/066plus_one.py)|Easy|

|67|[Add Binary](https://leetcode.com/problems/add-binary)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/067add_binary.py)|Easy|

|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/069sqrt(x).py)|Easy|

|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/070climbing_stairs.py)|Easy|

|71|[Simplify Path](https://leetcode.com/problems/simplify-path)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/071simplify_path.py)|Medium|

|73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/073set_matrix_zeroes.py)|Medium|

|74|[Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/074search_a_2d_matrix.py)|Medium|

|75|[Sort Colors](https://leetcode.com/problems/sort-colors)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/075sort_colors.py)|Medium|

|77|[Combinations](https://leetcode.com/problems/combinations)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/077combinations.py)|Medium|

|78|[Subsets](https://leetcode.com/problems/subsets)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/078subset.py)|Medium|

|79|[Word Search](https://leetcode.com/problems/word-search)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/079word_search.py)|Medium|

|80|[Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/080remove_duplicates_from_sorted_array2.py)|Medium|

|81|[Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/081search_in_rotated_sorted_array2.py)|Medium|

|82|[Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/082remove_duplicates_from_sorted_list2.py)|Medium|

|83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/083remove_duplicates_from_sorted_list.py)|Easy|

|86|[Partition List](https://leetcode.com/problems/partition-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/086partition_list.py)|Medium|

|88|[Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/088merge_sorted_array.py)|Easy|

|89|[Gray Code](https://leetcode.com/problems/gray-code)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/089gray_code.py)|Medium|

|90|[Subsets II](https://leetcode.com/problems/subsets-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/090subsets2.py)|Medium|

|91|[Decode Ways](https://leetcode.com/problems/decode-ways)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/091decode_ways.py)|Medium|

|92|[Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/092reverse_linked_list2.py)|Medium|

|93|[Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/093restore_ip_addresses.py)|Medium|

|94|[Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/094binary_tree_inorder_traversal.py)|Medium|

|100|[Same Tree](https://leetcode.com/problems/same-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/100same_tree.py)|Easy|

|101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/101symmetric_tree.py)|Easy|

|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/102binary_tree_level_order_traversal.py)|Medium|

|103|[Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/103binary_tree_zigzag_level_order_traversal.py)|Medium|

|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/104maximum_depth_of_binary_tree.py)|Easy|

|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/107binary_tree_level_order_traversal2.py)|Easy|

|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/108convert_sorted_array_to_binary_search_tree.py)|Easy|

|110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/110balanced_binary_tree.py)|Easy|

|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/111minimum_depth_of_binary_tree.py)|Easy|

|112|[Path Sum](https://leetcode.com/problems/path-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/112path_sum.py)|Easy|

|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/118pascal's_triangle.py)|Easy|

|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/119pascal's_triangle2.py)|Easy|

|120|[Triangle](https://leetcode.com/problems/triangle)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/120triangle.py)|Medium|

|121|[Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/121best_time_to_buy_and_sell_stock.py)|Easy|

|122|[Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/122best_time_to_buy_and_sell_stock2.py)|Easy|

|125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/125valid_palindrome.py)|Easy|

|136|[Single Number](https://leetcode.com/problems/single-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/136single_number.py)|Easy|

|141|[Linked List Cycle](https://leetcode.com/problems/linked-list-cycle)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/141linked_list_cycle.py)|Easy|

|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/144binary_tree_preorder_traversal.py)|Medium|

|148|[Sort List](https://leetcode.com/problems/sort-list/)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/148sort_list.py)|Medium|

|155|[Min Stack](https://leetcode.com/problems/min-stack)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/155min_stack.py)|Easy|

|157|[Read N Characters Given Read4](https://leetcode.com/problems/read-n-characters-given-read4)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/157read_n_characters_given_read4.py)|Easy|

|160|[Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/160intersection_of_two_linked_lists.py)|Easy|

|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/167two_sum2_input_array_is_sorted.py)|Easy|

|168|[	Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/168excel_sheet_column_title.py)|Easy|

|169|[Majority Element](https://leetcode.com/problems/majority-element)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/169majority_element.py)|Easy|

|170|[Two Sum III - Data structure design](https://leetcode.com/problems/two-sum-iii-data-structure-design)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/170two_sum3_data_structure_design.py)|Easy|

|171|[Excel Sheet Column Number](https://leetcode.com/problems/excel-sheet-column-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/171excel_sheet_column_number.py)|Easy|

|172|[Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/172factorial_trailing_zeroes.py)|Easy|

|175|[Combine Two Tables](https://leetcode.com/problems/combine-two-tables)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/175combine_two_tables.sql)|Easy|

|176|[Second Highest Salary](https://leetcode.com/problems/second-highest-salary)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/176second_highest_salary.sql)|Easy|

|181|[Employees Earning More Than Their Managers](https://leetcode.com/problems/employees-earning-more-than-their-managers)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/181employees_earning_more_than_their_managers.sql)|Easy|

|182|[Duplicate Emails](https://leetcode.com/problems/duplicate-emails)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/182duplicate_emails.sql)|Easy|

|183|[Customers Who Never Order](https://leetcode.com/problems/customers-who-never-order)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/183customers_who_never_order.sql)|Easy|

|189|[Rotate Array](https://leetcode.com/problems/rotate-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/189rotate_array.py)|Easy|

|190|[Reverse Bits](https://leetcode.com/problems/reverse-bits)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/190reverse_bits.py)|Easy|

|191|[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/191number_of_1_bits.py)|Easy|

|196|[Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/196delete_duplicate_emails.sql)|Easy|

|197|[Rising Temperature](https://leetcode.com/problems/rising-temperature)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/197rising_temperature.sql)|Easy|

|198|[House Robber](https://leetcode.com/problems/house-robber)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/198house_robber.py)|Easy|

|200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/200number_of_islands.py)|Medium|

|202|[Happy Number](https://leetcode.com/problems/happy-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/202happy_number.py)|Easy|

|203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/203remove_linked_list_elements.py)|Easy|

|204|[Count Primes](https://leetcode.com/problems/count-primes)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/204count_primes.py)|Easy|

|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/205isomorphic_strings.py)|Easy|

|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/206reverse_linked_list.py)|Easy|

|208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/208implement_trie_prefix_tree.py)|Medium|

|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/209minimum_size_subarray_sum.py)|Medium|

|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/217contains_duplicate.py)|Easy|

|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/219contains_duplicate2.py)|Easy|

|225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/225implement_stack_using_queues.py)|Easy|

|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/226Invert_binary_tree.py)|Easy|

|231|[Power of Two](https://leetcode.com/problems/power-of-two)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/231power_of_two.py)|Easy|

|232|[Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/232implement_queue_using_stacks.py)|Easy|

|234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/234palindrome_linked_list.py)|Easy|

|235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/235lowest_common_ancestor_of_a_binary_search_tree.py)|Easy|

|237|[Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/237delete_node_in_a_linked_list.py)|Easy|

|238|[Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/238product_of_array_except_self.py)|Medium|

|242|[Valid Anagram ](https://leetcode.com/problems/valid-anagram)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/242valid_anagram.py)|Easy|

|243|[Shortest Word Distance](https://leetcode.com/problems/shortest-word-distance)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/243shortest_word_distance.py)|Easy|

|246|[Strobogrammatic Number](https://leetcode.com/problems/strobogrammatic-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/246strobogrammatic_number.py)|Easy|

|252|[Meeting Rooms](https://leetcode.com/problems/meeting-rooms)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/252meeting_rooms.py)|Easy|

|256|[Paint House](https://leetcode.com/problems/paint-house)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/256paint_house.py)|Easy|

|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/257binary_tree_paths.py)|Easy|

|258|[Add Digits](https://leetcode.com/problems/add-digits)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/258add_digits.py)|Easy|

|261|[Graph Valid Tree](https://leetcode.com/problems/graph-valid-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/261graph_valid_tree.py)|Medium|

|263|[Ugly Number](https://leetcode.com/problems/ugly-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/263ugly_number.py)|Easy|

|266|[Palindrome Permutation ](https://leetcode.com/problems/palindrome-permutation)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/266palindrome_permutation.py)|Easy|

|268|[Missing Number](https://leetcode.com/problems/missing-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/268missing_number.py)|Easy|

|270|[Closest Binary Search Tree Value](https://leetcode.com/problems/closest-binary-search-tree-value)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/270closest_binary_search_tree_value.py)|Easy|

|276|[Paint Fence](https://leetcode.com/problems/paint-fence)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/276paint_fence.py)|Easy|

|278|[First Bad Version](https://leetcode.com/problems/first-bad-version)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/278first_bad_version.py)|Easy|

|283|[Move Zeroes](https://leetcode.com/problems/move-zeroes)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/283move_zeroes.py)|Easy|

|290|[Word Pattern](https://leetcode.com/problems/word-pattern)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/290word_pattern.py)|Easy|

|292|[Nim Game](https://leetcode.com/problems/nim-game)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/292nim_game.py)|Easy|

|293|[Flip Game](https://leetcode.com/problems/flip-game)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/293flip_game.py)|Easy|

|303|[Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/303range_sum_query-immutable.py)|Easy|

|323|[Number of Connected Components in an Undirected Graph](https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/323number_of_connected_components_in_an_undirected_graph.py)|Medium|

|325|[Maximum Size Subarray Sum Equals k](https://leetcode.com/problems/maximum-size-subarray-sum-equals-k/description/)|[Pyhon](https://github.com/LucasBoTang/LeetCode/blob/master/Python/325maximum_size_subarray_sum_equals_k.py)|Medium|

|326|[Power of Three](https://leetcode.com/problems/power-of-three)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/326power_of_three.py)|Easy|

|339|[Nested List Weight Sum](https://leetcode.com/problems/nested-list-weight-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/339nested_list_weight_sum.py)|Easy|

|342|[Power of Four](https://leetcode.com/problems/power-of-four)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/342power_of_four.py)|Easy|

|344|[Reverse String](https://leetcode.com/problems/reverse-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/344reverse_string.py)|Easy|

|345|[Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/345reverse_vowels_of_a_string.py)|Easy|

|346|[Moving Average from Data Stream](https://leetcode.com/problems/moving-average-from-data-stream)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/346moving_average_from_data_stream.py)|Easy|

|349|[Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/349intersection_of_two_arrays.py)|Easy|

|350|[Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/350intersection_of_two_arrays2.py)|Easy|

|359|[Logger Rate Limiter](https://leetcode.com/problems/logger-rate-limiter)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/359logger_rate_limiter.py)|Easy|

|367|[Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/367valid_perfect_square.py)|Easy|

|371|[Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/371sum_of_two_integers.py)|Easy|

|374|[Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/374guess_number_higher_or_lower.py)|Easy|

|383|[Ransom Note](https://leetcode.com/problems/ransom-note)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/383ransom_note.py)|Easy|

|387|[First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/387first_unique_character_in_a_string.py)|Easy|

|389|[Find the Difference](https://leetcode.com/problems/find-the-difference)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/389find_the_difference.py)|Easy|

|400|[Nth Digit](https://leetcode.com/problems/nth-digit)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/400nth_digit.py)|Easy|

|401|[Binary Watch](https://leetcode.com/problems/binary-watch)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/401binary_watch.py)|Easy|

|404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/404sum_of_left_leaves.py)|Easy|

|405|[Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/405convert_a_number_to_hexadecimal.py)|Easy|

|408|[Valid Word Abbreviation](https://leetcode.com/problems/valid-word-abbreviation)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/408valid_word_abbreviation.py)|Easy|

|409|[Longest Palindrome](https://leetcode.com/problems/longest-palindrome)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/409longest_palindrome.py)|Easy|

|412|[Fizz Buzz](https://leetcode.com/problems/fizz-buzz)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/412fizz_buzz.py)|Easy|

|414|[Third Maximum Number](https://leetcode.com/problems/third-maximum-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/414third_xaximum_number.py)|Easy|

|415|[Add Strings](https://leetcode.com/problems/add-strings)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/415add_strings.py)|Easy|

|416|[Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/416partition_equal_subset_sum.py)|Medium|

|422|[Valid Word Square](https://leetcode.com/problems/valid-word-square)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/422valid_word_square.py)|Easy|

|427|[Construct Quad Tree](https://leetcode.com/problems/construct-quad-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/427construct_quad_tree.py)|Easy|

|429|[N-ary Tree Level Order Traversal](https://leetcode.com/problems/n-ary-tree-level-order-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/429n-ary_tree_level_order_traversal.py)|Easy|

|434|[Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/434number_of_segments_in_a_string.py)|Easy|

|437|[Path Sum III](https://leetcode.com/problems/path-sum-iii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/437path_sum3.py)|Easy|

|438|[Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/438find_all_anagrams_in_a_string.py)|Easy|

|441|[Arranging Coins](https://leetcode.com/problems/arranging-coins)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/441arranging_coins.py)|Easy|

|443|[String Compression](https://leetcode.com/problems/string-compression)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/443string_compression.py)|Easy|

|447|[Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/447number_of_boomerangs.py)|Easy|

|448|[Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/448find_all_numbers_disappeared_in_an_array.py)|Easy|

|453|[Minimum Moves to Equal Array Elements](https://leetcode.com/problems/minimum-moves-to-equal-array-elements)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/453minimum_moves_to_equal_array_elements.py)|Easy|

|455|[Assign Cookies](https://leetcode.com/problems/assign-cookies)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/455assign_cookies.py)|Easy|

|458|[Poor Pigs](https://leetcode.com/problems/poor-pigs)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/458poor_pigs.py)|Easy|

|459|[Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/459repeated_substring_pattern.py)|Easy|

|461|[Hamming Distance](https://leetcode.com/problems/hamming-distance)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/461hamming_distance.py)|Easy|

|463|[Island Perimeter](https://leetcode.com/problems/island-perimeter)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/463island_perimeter.py)|Easy|

|468|[Validate IP Address](https://leetcode.com/problems/validate-ip-address)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/468validate_ip_address.py)|Medium|

|475|[Heaters](https://leetcode.com/problems/heaters)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/475heaters.py)|Easy|

|476|[Number Complement](https://leetcode.com/problems/number-complement)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/476number_complement.py)|Easy|

|479|[Largest Palindrome Product](https://leetcode.com/problems/largest-palindrome-product)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/479largest_palindrome_product.py)|Easy|

|482|[License Key Formatting](https://leetcode.com/problems/license-key-formatting)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/482license_key_formatting.py)|Easy|

|485|[Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/485max_consecutive_ones.py)|Easy|

|492|[Construct the Rectangle](https://leetcode.com/problems/construct-the-rectangle)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/492construct_the_rectangle.py)|Easy|

|496|[Next Greater Element I](https://leetcode.com/problems/next-greater-element-i)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/496next_greater_element1.py)|Easy|

|500|[Keyboard Row](https://leetcode.com/problems/keyboard-row)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/500keyboard_row.py)|Easy|

|501|[Find Mode in Binary Search Tree](https://leetcode.com/problems/find-mode-in-binary-search-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/501find_mode_in_binary_search_tree.py)|Easy|

|504|[Base 7](https://leetcode.com/problems/base-7)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/504base_7.py)|Easy|

|506|[Relative Ranks](https://leetcode.com/problems/relative-ranks)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/506relative_ranks.py)|Easy|

|507|[Perfect Number](https://leetcode.com/problems/perfect-number)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/507perfect_number.py)|Easy|

|520|[Detect Capital](https://leetcode.com/problems/detect-capital)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/520detect_capital.py)|Easy|

|521|[Longest Uncommon Subsequence I](https://leetcode.com/problems/longest-uncommon-subsequence-i)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/521longest_uncommon_subsequence1.py)|Easy|

|530|[Minimum Absolute Difference in BST](https://leetcode.com/problems/minimum-absolute-difference-in-bst)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/530minimum_absolute_difference_in_BST.py)|Easy|

|532|[K-diff Pairs in an Array](https://leetcode.com/problems/k-diff-pairs-in-an-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/532k-diff_pairs_in_an_array.py)|Easy|

|538|[Convert BST to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/538convert_bst_to_greater_tree.py)|Easy|

|541|[Reverse String II](https://leetcode.com/problems/reverse-string-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/541reverse_string2.py)|Easy|

|543|[Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/543diameter_of_binary_tree.py)|Easy|

|551|[Student Attendance Record I](https://leetcode.com/problems/student-attendance-record-i)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/551student_attendance_record1.py)|Easy|

|557|[Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/557reverse_words_in_a_string3.py)|Easy|

|558|[Quad Tree Intersection](https://leetcode.com/problems/quad-tree-intersection)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/558quad_tree_intersection.py)|Easy|

|559|[Maximum Depth of N-ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/559maximum_depth_of_n-ary_tree.py)|Easy|

|560|[Subarray Sum Equals K](https://leetcode.com/problems/subarray-sum-equals-k)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/560subarray_sum_equals_k.py)|Medium|

|561|[Array Partition I](https://leetcode.com/problems/array-partition-i)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/561array_partition1.py)|Easy|

|563|[Binary Tree Tilt](https://leetcode.com/problems/binary-tree-tilt)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/563binary_tree_tilt.py)|Easy|

|566|[Reshape the Matrix](https://leetcode.com/problems/reshape-the-matrix)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/566reshape_the_matrix.py)|Easy|

|572|[Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/572subtree_of_another_tree.py)|Easy|

|575|[Distribute Candies](https://leetcode.com/problems/distribute-candies)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/575distribute_candies.py)|Easy|

|577|[Employee Bonus](https://leetcode.com/problems/employee-bonus)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/577employee_bonus.sql)|Easy|

|581|[Shortest Unsorted Continuous Subarray](https://leetcode.com/problems/shortest-unsorted-continuous-subarray)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/581shortest_unsorted_continuous_subarray.py)|Easy|

|584|[Find Customer Referee](https://leetcode.com/problems/find-customer-referee)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/584find_customer_referee.sql)|Easy|

|586|[Customer Placing the Largest Number of Orders](https://leetcode.com/problems/customer-placing-the-largest-number-of-orders)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/586customer_placing_the_largest_number_of_orders.sql)|Easy|

|589|[N-ary Tree Preorder Traversal](https://leetcode.com/problems/n-ary-tree-preorder-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/589n-ary_tree_preorder_traversal.py)|Easy|

|590|[N-ary Tree Postorder Traversal](https://leetcode.com/problems/n-ary-tree-postorder-traversal)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/590n-ary_tree_postorder_traversal.py)|Easy|

|594|[Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/594longest_harmonious_subsequence.py)|Easy|

|595|[Big Countries](https://leetcode.com/problems/big-countries)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/595big_countries.sql)|Easy|

|596|[Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/596classes_more_than_5_students.sql)|Easy|

|597|[Friend Requests I: Overall Acceptance Rate](https://leetcode.com/problems/friend-requests-i-overall-acceptance-rate)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/597friend_requests1_overall_acceptance_rate.sql)|Easy|

|598|[Range Addition II](https://leetcode.com/problems/range-addition-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/598range_addition2.py)|Easy|

|599|[Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/599minimum_index_sum_of_two_lists.py)|Easy|

|603|[Consecutive Available Seats](https://leetcode.com/problems/consecutive-available-seats)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/603consecutive_available_seats.sql)|Easy|

|604|[Design Compressed String Iterator](https://leetcode.com/problems/design-compressed-string-iterator)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/604design_compressed_string_iterator.py)|Easy|

|605|[Can Place Flowers](https://leetcode.com/problems/can-place-flowers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/605can_place_flowers.py)|Easy|

|606|[Construct String from Binary Tree](https://leetcode.com/problems/construct-string-from-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/606construct_string_from_binary_tree.py)|Easy|

|607|[Sales Person](https://leetcode.com/problems/sales-person)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/607sales_person.sql)|Easy|

|610|[Triangle Judgement](https://leetcode.com/problems/triangle-judgement)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/610triangle_judgement.sql)|Easy|

|613|[Shortest Distance in a Line](https://leetcode.com/problems/shortest-distance-in-a-line)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/613shortest_distance_in_a_line.sql)|Easy|

|617|[Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/617merge_two_binary_trees.py)|Easy|

|619|[Biggest Single Number](https://leetcode.com/problems/biggest-single-number)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/619biggest_single_number.sql)|Easy|

|620|[Not Boring Movies](https://leetcode.com/problems/not-boring-movies)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/620not_boring_movies.sql)|Easy|

|624|[Maximum Distance in Arrays](https://leetcode.com/problems/maximum-distance-in-arrays)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/624maximum_distance_in_arrays.py)|Easy|

|627|[Swap Salary](https://leetcode.com/problems/swap-salary)|[SQL](https://github.com/LucasBoTang/LeetCode/blob/master/SQL/627swap_salary.sql)|Easy|

|628|[Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/628maximum_product_of_three_numbers.py)|Easy|

|633|[Sum of Square Numbers](https://leetcode.com/problems/sum-of-square-numbers)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/633sum_of_square_numbers.py)|Easy|

|637|[Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/637average_of_levels_in_binary_tree.py)|Easy|

|643|[Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/643maximum_average_subarray1.py)|Easy|

|645|[Set Mismatch](https://leetcode.com/problems/set-mismatch)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/645set_mismatch.py)|Easy|

|653|[Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/653two_sum5_input_is_a_bst.py)|Easy|

|657|[Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/657judge_route_circle.py)|Easy|

|661|[Image Smoother](https://leetcode.com/problems/image-smoother)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/661image_smoother.py)|Easy|

|665|[Non-decreasing Array](https://leetcode.com/problems/non-decreasing-array)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/665non-decreasing_array.py)|Easy|

|669|[Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/669trim_a_binary_search_tree.py)|Easy|

|671|[Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/671second_minimum_node_in_a_binary_tree.py)|Easy|

|674|[Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/674longest_continuous_increasing_subsequence.py)|Easy|

|680|[Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/680valid_palindrome2.py)|Easy|

|682|[Baseball Game](https://leetcode.com/problems/baseball-game)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/682baseball_game.py)|Easy|

|686|[Repeated String Match](https://leetcode.com/problems/repeated-string-match)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/686repeated_string_match.py)|Easy|

|687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/687longest_univalue_path.py)|Easy|

|690|[Employee Importance](https://leetcode.com/problems/employee-importance)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/690employee_importance.py)|Easy|

|693|[Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/693binary_number_with_alternating_bits.py)|Easy|

|695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/695max_area_of_island.py)|Easy|

|696|[Count Binary Substrings](https://leetcode.com/problems/count-binary-substrings)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/696count_binary_substrings.py)|Easy|

|713|[Subarray Product Less Than K](https://leetcode.com/problems/subarray-product-less-than-k)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/713subarray_product_less_than_k.py)|Medium|

|987|[Vertical Order Traversal of a Binary Tree](https://leetcode.com/problems/vertical-order-traversal-of-a-binary-tree/)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/987vertical_order_traversal_of_a_binary_tree.py)|Medium|

|1052|[Grumpy Bookstore Owner](https://leetcode.com/problems/grumpy-bookstore-owner)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1052grumpy_bookstore_owner.py)|Medium|

|1151|[Minimum Swaps to Group All 1's Together](https://leetcode.com/problems/minimum-swaps-to-group-all-1s-together)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1151minimum_swaps_to_group_all_1s_together.py)|Medium|

|1155|[Number of Dice Nolls with Target Sum](https://leetcode.com/problems/number-of-dice-rolls-with-target-sum)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1155number_of_dice_rolls_with_target_sum.py)|Medium|

|1197|[Minimum Knight Moves](https://leetcode.com/problems/minimum-knight-moves)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1197minimum_knight_moves.py)|Medium|

|1245|[Tree Diameter](https://leetcode.com/problems/tree-diameter)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1245tree_diameter.py)|Medium|

|1492|[The kth Factor of n](https://leetcode.com/problems/the-kth-factor-of-n)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1492the_kth_factor_of_n)|Medium|

|1676|[Lowest Common Ancestor of a Binary Tree IV](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-iv/)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/1676lowest_common_ancestor_of_a_binary_tree4.py)|Medium|

|2355|[Maximum Number of Books You Can Take](https://leetcode.com/problems/maximum-number-of-books-you-can-take)|[~~Python~~](https://leetcode.com/problems/maximum-number-of-books-you-can-take)|Hard|

|2405|[Optimal Partition of String](https://leetcode.com/problems/optimal-partition-of-string)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/2405optimal_partition_of_string.py)|Medium|

|2422|[Merge Operations to Turn Array Into a Palindrome](https://leetcode.com/problems/merge-operations-to-turn-array-into-a-palindrome)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/2422merge_operations_to_turn_array_into_a_palindrome.py)|Medium|

|2534|[Time Taken to Cross the Door](https://leetcode.com/problems/time-taken-to-cross-the-door)|[Python](https://github.com/LucasBoTang/LeetCode/blob/master/Python/2534time_taken_to_cross_the_door.py)|Hard|