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https://github.com/remy727/leetcode

LeetCode Ruby Solutions
https://github.com/remy727/leetcode
algorithms leetcode leetcode-ruby leetcode-solutions ruby
Last synced: 3 months ago
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LeetCode Ruby Solutions
Host: GitHub
URL: https://github.com/remy727/leetcode
Owner: remy727
Created: 2023-02-10T08:27:27.000Z (almost 2 years ago)
Default Branch: main
Last Pushed: 2024-10-29T21:16:28.000Z (3 months ago)
Last Synced: 2024-10-30T01:04:40.513Z (3 months ago)
Topics: algorithms, leetcode, leetcode-ruby, leetcode-solutions, ruby
Language: Ruby
Homepage:
Size: 761 KB
Stars: 14
Watchers: 1
Forks: 3
Open Issues: 0
Metadata Files:
- Readme: README.md
Awesome Lists containing this project

README

        # LeetCode

### Algorithms

| # | Title | Solution | Difficulty |

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

| 1 | Two Sum | [Ruby](./algorithms/ruby/0001-two-sum.rb) | Easy |

| 2 | Add Two Numbers | [Ruby](./algorithms/ruby/0002-add-two-numbers.rb) | Medium |

| 3 | Longest Substring Without Repeating Characters | [Ruby](./algorithms/ruby/0003-longest-substring-without-repeating-characters.rb) | Medium |

| 4 | Median of Two Sorted Arrays | [Ruby](./algorithms/ruby/0004-median-of-two-sorted-arrays.rb) | Hard |

| 5 | Longest Palindromic Substring | [Ruby](./algorithms/ruby/0005-longest-palindromic-substring.rb) | Medium |

| 6 | Verifying an Alien Dictionary | [Ruby](./algorithms/ruby/0006-zigzag-conversion.rb) | Medium |

| 7 | Reverse Integer | [Ruby](./algorithms/ruby/0007-reverse-integer.rb) | Medium |

| 8 | String to Integer (atoi) | [Ruby](./algorithms/ruby/0008-string-to-integer-atoi.rb) | Medium |

| 9 | Palindrome Number | [Ruby](./algorithms/ruby/0009-palindrome-number.rb) | Easy |

| 10 | Regular Expression Matching | [Ruby](./algorithms/ruby/0010-regular-expression-matching.rb) | Hard |

| 11 | Container With Most Water | [Ruby](./algorithms/ruby/0011-container-with-most-water.rb) | Medium |

| 12 | Integer to Roman | [Ruby](./algorithms/ruby/0012-integer-to-roman.rb) | Medium |

| 13 | Roman to Integer | [Ruby](./algorithms/ruby/0013-roman-to-integer.rb) | Easy |

| 14 | Longest Common Prefix | [Ruby](./algorithms/ruby/0014-longest-common-prefix.rb) | Easy |

| 15 | 3Sum | [Ruby](./algorithms/ruby/0015-3sum.rb) | Medium |

| 16 | 3Sum Closest | [Ruby](./algorithms/ruby/0016-3sum-closest.rb) | Medium |

| 17 | Letter Combinations of a Phone Number | [Ruby](./algorithms/ruby/0017-letter-combinations-of-a-phone-number.rb) | Medium |

| 18 | 4Sum | [Ruby](./algorithms/ruby/0018-4sum.rb) | Medium |

| 19 | Remove Nth Node From End of List | [Ruby](./algorithms/ruby/0019-remove-nth-node-from-end-of-list.rb) | Medium |

| 20 | Valid Parentheses | [Ruby](./algorithms/ruby/0020-valid-parentheses.rb) | Easy |

| 21 | Merge Two Sorted Lists | [Ruby](./algorithms/ruby/0021-merge-two-sorted-lists.rb) | Easy |

| 22 | Generate Parentheses | [Ruby](./algorithms/ruby/0022-generate-parentheses.rb) | Medium |

| 23 | Merge k Sorted Lists | [Ruby](./algorithms/ruby/0023-merge-k-sorted-lists.rb) | Hard |

| 24 | Swap Nodes in Pairs | [Ruby](./algorithms/ruby/0024-swap-nodes-in-pairs.rb) | Medium |

| 25 | Reverse Nodes in k-Group | [Ruby](./algorithms/ruby/0025-reverse-nodes-in-k-group.rb) | Hard |

| 26 | Remove Duplicates from Sorted Array | [Ruby](./algorithms/ruby/0026-remove-duplicates-from-sorted-array.rb) | Easy |

| 27 | Remove Element | [Ruby](./algorithms/ruby/0027-remove-element.rb) | Easy |

| 28 | Find the Index of the First Occurrence in a String | [Ruby](./algorithms/ruby/0028-find-the-index-of-the-first-occurrence-in-a-string.rb) | Medium |

| 30 | Substring with Concatenation of All Words | [Ruby](./algorithms/ruby/0030-substring-with-concatenation-of-all-words.rb) | Hard |

| 33 | Search in Rotated Sorted Array | [Ruby](./algorithms/ruby/0033-search-in-rotated-sorted-array.rb) | Medium |

| 34 | Find First and Last Position of Element in Sorted Array | [Ruby](./algorithms/ruby/0034-find-first-and-last-position-of-element-in-sorted-array.rb) | Medium |

| 35 | Search Insert Position | [Ruby](./algorithms/ruby/0035-search-insert-position.rb) | Easy |

| 36 | Valid Sudoku | [Ruby](./algorithms/ruby/0036-valid-sudoku.rb) | Medium |

| 39 | Combination Sum | [Ruby](./algorithms/ruby/0039-combination-sum.rb) | Medium |

| 40 | Combination Sum II | [Ruby](./algorithms/ruby/0040-combination-sum-ii.rb) | Medium |

| 42 | Trapping Rain Water | [Ruby](./algorithms/ruby/0042-trapping-rain-water.rb) | Hard |

| 43 | Multiply Strings | [Ruby](./algorithms/ruby/0043-multiply-strings.rb) | Medium |

| 45 | Jump Game II | [Ruby](./algorithms/ruby/0045-jump-game-ii.rb) | Medium |

| 46 | Permutations | [Ruby](./algorithms/ruby/0046-permutations.rb) | Medium |

| 48 | Rotate Image | [Ruby](./algorithms/ruby/0048-rotate-image.rb) | Medium |

| 49 | Group Anagrams | [Ruby](./algorithms/ruby/0049-group-anagrams.rb) | Medium |

| 50 | Pow(x, n) | [Ruby](./algorithms/ruby/0050-powx-n.rb) | Medium |

| 52 | N-Queens II | [Ruby](./algorithms/ruby/0052-n-queens-ii.rb) | Hard |

| 53 | Maximum Subarray | [Ruby](./algorithms/ruby/0053-maximum-subarray.rb) | Medium |

| 54 | Spiral Matrix | [Ruby](./algorithms/ruby/0054-spiral-matrix.rb) | Medium |

| 55 | Jump Game | [Ruby](./algorithms/ruby/0055-jump-game.rb) | Medium |

| 58 | Length of Last Word | [Ruby](./algorithms/ruby/0058-length-of-last-word.rb) | Easy |

| 59 | Spiral Matrix II | [Ruby](./algorithms/ruby/0059-spiral-matrix-ii.rb) | Medium |

| 61 | Rotate List | [Ruby](./algorithms/ruby/0061-rotate-list.rb) | Medium |

| 62 | Unique Paths | [Ruby](./algorithms/ruby/0062-unique-paths.rb) | Medium |

| 63 | Unique Paths II | [Ruby](./algorithms/ruby/0063-unique-paths-ii.rb) | Medium |

| 64 | Minimum Path Sum | [Ruby](./algorithms/ruby/0064-minimum-path-sum.rb) | Medium |

| 66 | Plus One | [Ruby](./algorithms/ruby/0066-plus-one.rb) | Easy |

| 67 | Add Binary | [Ruby](./algorithms/ruby/0067-add-binary.rb) [Python3](./algorithms/python3/0067-add-binary.py) | Easy |

| 68 | Text Justification | [Ruby](./algorithms/ruby/0068-text-justification.rb) | Hard |

| 69 | Sqrt(x) | [Ruby](./algorithms/ruby/0069-sqrtx.rb) | Easy |

| 70 | Climbing Stairs | [Ruby](./algorithms/ruby/0070-climbing-stairs.rb) | Easy |

| 71 | Climbing Stairs | [Ruby](./algorithms/ruby/0070-climbing-stairs.rb) | Medium |

| 72 | Edit Distance | [Ruby](./algorithms/ruby/0072-edit-distance.rb) | Hard |

| 73 | Set Matrix Zeroes | [Ruby](./algorithms/ruby/0073-set-matrix-zeroes.rb) | Medium |

| 74 | Search a 2D Matrix | [Ruby](./algorithms/ruby/0074-search-a-2d-matrix.rb) | Medium |

| 76 | Minimum Window Substring | [Ruby](./algorithms/ruby/0076-minimum-window-substring.rb) | Hard |

| 77 | Combinations | [Ruby](./algorithms/ruby/0077-combinations.rb) | Medium |

| 79 | Word Search | [Ruby](./algorithms/ruby/0079-word-search.rb) | Medium |

| 80 | Remove Duplicates from Sorted Array II | [Ruby](./algorithms/ruby/0080-remove-duplicates-from-sorted-array-ii.rb) | Medium |

| 81 | Search in Rotated Sorted Array II | [Ruby](./algorithms/ruby/0081-search-in-rotated-sorted-array-ii.rb) | Medium |

| 82 | Remove Duplicates from Sorted List II | [Ruby](./algorithms/ruby/0082-remove-duplicates-from-sorted-list-ii.rb) | Medium |

| 86 | Partition List | [Ruby](./algorithms/ruby/0086-partition-list.rb) | Medium |

| 87 | Scramble String | [Ruby](./algorithms/ruby/0087-scramble-string.rb) | Hard |

| 88 | Merge Sorted Array | [Ruby](./algorithms/ruby/0088-merge-sorted-array.rb) | Easy |

| 91 | Decode Ways | [Ruby](./algorithms/ruby/0091-decode-ways.rb) | Medium |

| 92 | Reverse Linked List II | [Ruby](./algorithms/ruby/0092-reverse-linked-list-ii.rb) | Medium |

| 94 | Binary Tree Inorder Traversal | [Ruby](./algorithms/ruby/0094-binary-tree-inorder-traversal.rb) | Easy |

| 95 | Unique Binary Search Trees II | [Ruby](./algorithms/ruby/0095-unique-binary-search-trees-ii.rb) | Medium |

| 97 | Interleaving String | [Ruby](./algorithms/ruby/0097-interleaving-string.rb) | Medium |

| 98 | Validate Binary Search Tree | [Ruby](./algorithms/ruby/0098-validate-binary-search-tree.rb) | Medium |

| 100 | Same Tree | [Ruby](./algorithms/ruby/0100-same-tree.rb) | Easy |

| 101 | Symmetric Tree | [Ruby](./algorithms/ruby/0101-symmetric-tree.rb) | Easy |

| 102 | Binary Tree Level Order Traversal | [Ruby](./algorithms/ruby/0102-binary-tree-level-order-traversal.rb) | Medium |

| 103 | Binary Tree Zigzag Level Order Traversal | [Ruby](./algorithms/ruby/0103-binary-tree-zigzag-level-order-traversal.rb) | Medium |

| 104 | Maximum Depth of Binary Tree | [Ruby](./algorithms/ruby/0104-maximum-depth-of-binary-tree.rb) [Python3](./algorithms/python3/0104-maximum-depth-of-binary-tree.py) | Easy |

| 105 | Construct Binary Tree from Preorder and Inorder Traversal | [Ruby](./algorithms/ruby/0105-construct-binary-tree-from-preorder-and-inorder-traversal.rb) | Medium |

| 106 | Construct Binary Tree from Inorder and Postorder Traversal | [Ruby](./algorithms/ruby/0106-construct-binary-tree-from-inorder-and-postorder-traversal.rb) | Medium |

| 108 | Convert Sorted Array to Binary Search Tree | [Ruby](./algorithms/ruby/0108-convert-sorted-array-to-binary-search-tree.rb) | Easy |

| 109 | Convert Sorted List to Binary Search Tree | [Ruby](./algorithms/ruby/0109-convert-sorted-list-to-binary-search-tree.rb) | Medium |

| 110 | Balanced Binary Tree | [Ruby](./algorithms/ruby/0110-balanced-binary-tree.rb) | Easy |

| 111 | Minimum Depth of Binary Tree | [Ruby](./algorithms/ruby/0111-minimum-depth-of-binary-tree.rb) | Easy |

| 112 | Path Sum | [Ruby](./algorithms/ruby/0112-path-sum.rb) | Easy |

| 113 | Path Sum II | [Ruby](./algorithms/ruby/0113-path-sum-ii.rb) | Medium |

| 114 | Flatten Binary Tree to Linked List | [Ruby](./algorithms/ruby/0114-flatten-binary-tree-to-linked-list.rb) | Medium |

| 117 | Populating Next Right Pointers in Each Node II | [Ruby](./algorithms/ruby/0117-populating-next-right-pointers-in-each-node-ii.rb) | Medium |

| 118 | Pascal's Triangle | [Ruby](./algorithms/ruby/0118-pascals-triangle.rb) | Easy |

| 119 | Pascal's Triangle II | [Ruby](./algorithms/ruby/0119-pascals-triangle-ii.rb) | Easy |

| 120 | Triangle | [Ruby](./algorithms/ruby/0120-triangle.rb) | Medium |

| 121 | Best Time to Buy and Sell Stock | [Ruby](./algorithms/ruby/0121-best-time-to-buy-and-sell-stock.rb) | Easy |

| 122 | Best Time to Buy and Sell Stock II | [Ruby](./algorithms/ruby/0122-best-time-to-buy-and-sell-stock-ii.rb) | Medium |

| 123 | Best Time to Buy and Sell Stock III | [Ruby](./algorithms/ruby/0123-best-time-to-buy-and-sell-stock-iii.rb) | Hard |

| 124 | Binary Tree Maximum Path Sum | [Ruby](./algorithms/ruby/0124-binary-tree-maximum-path-sum.rb) | Hard |

| 125 | Valid Palindrome | [Ruby](./algorithms/ruby/0125-valid-palindrome.rb) | Easy |

| 127 | Word Ladder | [Ruby](./algorithms/ruby/0127-word-ladder.rb) | Hard |

| 128 | Longest Consecutive Sequence | [Ruby](./algorithms/ruby/0128-longest-consecutive-sequence.rb) | Medium |

| 129 | Sum Root to Leaf Numbers | [Ruby](./algorithms/ruby/0129-sum-root-to-leaf-numbers.rb) | Medium |

| 130 | Surrounded Regions | [Ruby](./algorithms/ruby/0130-surrounded-regions.rb) | Medium |

| 133 | Clone Graph | [Ruby](./algorithms/ruby/0133-clone-graph.rb) | Medium |

| 134 | Gas Station | [Ruby](./algorithms/ruby/0134-gas-station.rb) | Easy |

| 135 | Candy | [Ruby](./algorithms/ruby/0135-candy.rb) | Hard |

| 136 | Single Number | [Ruby](./algorithms/ruby/0136-single-number.rb) | Easy |

| 137 | Single Number II | [Ruby](./algorithms/ruby/0137-single-number-ii.rb) | Medium |

| 138 |Copy List with Random Pointer | [Ruby](./algorithms/ruby/0138-copy-list-with-random-pointer.rb) | Medium |

| 139 | Word Break | [Ruby](./algorithms/ruby/0139-word-break.rb) | Medium |

| 141 | Linked List Cycle | [Ruby](./algorithms/ruby/0141-linked-list-cycle.rb) | Easy |

| 142 | Linked List Cycle II | [Ruby](./algorithms/ruby/0142-linked-list-cycle-ii.rb) | Medium |

| 146 | LRU Cache | [Ruby](./algorithms/ruby/0146-lru-cache.rb) | Medium |

| 148 | Sort List | [Ruby](./algorithms/ruby/0148-sort-list.rb) | Medium |

| 149 | Max Points on a Line | [Ruby](./algorithms/ruby/0149-max-points-on-a-line.rb) | Hard |

| 150 | Evaluate Reverse Polish Notation | [Ruby](./algorithms/ruby/0150-evaluate-reverse-polish-notation.rb) | Medium |

| 151 | Reverse Words in a String | [Ruby](./algorithms/ruby/0151-reverse-words-in-a-string.rb) | Medium |

| 152 | Maximum Product Subarray | [Ruby](./algorithms/ruby/0152-maximum-product-subarray.rb) | Medium |

| 153 | Find Minimum in Rotated Sorted Array | [Ruby](./algorithms/ruby/0153-find-minimum-in-rotated-sorted-array.rb) | Medium |

| 155 | Min Stack | [Ruby](./algorithms/ruby/0155-min-stack.rb) | Medium |

| 162 | Find Peak Element | [Ruby](./algorithms/ruby/0162-find-peak-element.rb) | Medium |

| 167 | Two Sum II - Input Array Is Sorted | [Ruby](./algorithms/ruby/0167-two-sum-ii-input-array-is-sorted.rb) | Medium |

| 168 | Excel Sheet Column Title | [Ruby](./algorithms/ruby/0168-excel-sheet-column-title.rb) | Easy |

| 169 | Majority Element | [Ruby](./algorithms/ruby/0169-majority-element.rb) | Easy |

| 172 | Factorial Trailing Zeroes | [Ruby](./algorithms/ruby/0172-factorial-trailing-zeroes.rb) | Medium |

| 173 | Binary Search Tree Iterator | [Ruby](./algorithms/ruby/0173-binary-search-tree-iterato.rb) | Medium |

| 188 | Best Time to Buy and Sell Stock IV | [Ruby](./algorithms/ruby/0188-best-time-to-buy-and-sell-stock-iv.rb) | Hard |

| 189 | Rotate Array | [Ruby](./algorithms/ruby/0189-rotate-array.rb) | Medium |

| 190 | Reverse Bits | [Ruby](./algorithms/ruby/0190-reverse-bits.rb) | Easy |

| 191 | Number of 1 Bits | [Ruby](./algorithms/ruby/0191-number-of-1-bits.rb) | Easy |

| 198 | House Robber | [Ruby](./algorithms/ruby/0198-house-robber.rb) | Medium |

| 199 | Binary Tree Right Side View | [Ruby](./algorithms/ruby/0199-binary-tree-right-side-view.rb) | Medium |

| 200 | Number of Islands | [Ruby](./algorithms/ruby/0200-number-of-islands.rb) | Medium |

| 201 | Bitwise AND of Numbers Range | [Ruby](./algorithms/ruby/0201-bitwise-and-of-numbers-range.rb) | Medium |

| 202 | Happy Number | [Ruby](./algorithms/ruby/0202-happy-number.rb) | Easy |

| 205 | Isomorphic Strings | [Ruby](./algorithms/ruby/0205-isomorphic-strings.rb) | Easy |

| 206 | Reverse Linked List | [Ruby](./algorithms/ruby/0206-reverse-linked-list.rb) | Easy |

| 207 | Course Schedule | [Ruby](./algorithms/ruby/0207-course-schedule.rb) | Medium |

| 208 | Implement Trie (Prefix Tree) | [Ruby](./algorithms/ruby/0208-implement-trie-prefix-tree.rb) | Medium |

| 209 | Minimum Size Subarray Sum | [Ruby](./algorithms/ruby/0209-minimum-size-subarray-sum.rb) | Medium |

| 210 | Course Schedule II | [Ruby](./algorithms/ruby/0210-course-schedule-ii.rb) | Medium |

| 211 | Design Add and Search Words Data Structure | [Ruby](./algorithms/ruby/0211-design-add-and-search-words-data-structure.rb) | Medium |

| 212 | Word Search II | [Ruby](./algorithms/ruby/0212-word-search-ii.rb) | Hard |

| 215 | Kth Largest Element in an Array | [Ruby](./algorithms/ruby/0215-kth-largest-element-in-an-array.rb) | Medium |

| 216 | Combination Sum III | [Ruby](./algorithms/ruby/0216-combination-sum-iii.rb) | Medium |

| 219 | Contains Duplicate II | [Ruby](./algorithms/ruby/0219-contains-duplicate-ii.rb) | Easy |

| 221 | Maximal Square | [Ruby](./algorithms/ruby/0221-maximal-square.rb) | Medium |

| 222 | Count Complete Tree Nodes | [Ruby](./algorithms/ruby/0222-count-complete-tree-nodes.rb) | Medium |

| 224 | Basic Calculator | [Ruby](./algorithms/ruby/0224-basic-calculator.rb) | Hard |

| 225 | Implement Stack using Queues | [Ruby](./algorithms/ruby/0225-implement-stack-using-queues.rb) | Easy |

| 226 | Invert Binary Tree | [Ruby](./algorithms/ruby/0226-invert-binary-tree.rb) | Easy |

| 227 | Basic Calculator II | [Ruby](./algorithms/ruby/0227-basic-calculator-ii.rb) | Medium |

| 228 | Summary Ranges | [Ruby](./algorithms/ruby/0228-summary-ranges.rb) | Easy |

| 229 | Majority Element II | [Ruby](./algorithms/ruby/0229-majority-element-ii.rb) | Medium |

| 230 | Kth Smallest Element in a BST | [Ruby](./algorithms/ruby/0230-kth-smallest-element-in-a-bst.rb) | Medium |

| 232 | Implement Queue using Stacks | [Ruby](./algorithms/ruby/0232-implement-queue-using-stacks.rb) | Easy |

| 234 | Palindrome Linked List | [Ruby](./algorithms/ruby/0234-palindrome-linked-list.rb) | Easy |

| 235 | Lowest Common Ancestor of a Binary Search Tree | [Ruby](./algorithms/ruby/0235-lowest-common-ancestor-of-a-binary-search-tree.rb) | Medium |

| 236 | Lowest Common Ancestor of a Binary Tree | [Ruby](./algorithms/ruby/0236-lowest-common-ancestor-of-a-binary-tree.rb) | Medium |

| 238 | Product of Array Except Self | [Ruby](./algorithms/ruby/0238-product-of-array-except-self.rb) | Medium |

| 239 | Sliding Window Maximum | [Ruby](./algorithms/ruby/0239-sliding-window-maximum.rb) | Hard |

| 242 | Valid Anagram | [Ruby](./algorithms/ruby/0242-valid-anagram.rb) | Easy |

| 258 | Add Digits | [Ruby](./algorithms/ruby/0258-add-digits.rb) | Easy |

| 274 | H-Index | [Ruby](./algorithms/ruby/0274-h-index.rb) | Medium |

| 278 | First Bad Version | [Ruby](./algorithms/ruby/0278-first-bad-version.rb) | Easy |

| 283 | Move Zeroes | [Ruby](./algorithms/ruby/0283-move-zeroes.rb) | Easy |

| 287 | Find the Duplicate Number | [Ruby](./algorithms/ruby/0287-find-the-duplicate-number.rb) | Medium |

| 289 | Game of Life | [Ruby](./algorithms/ruby/0289-game-of-life.rb) | Medium |

| 290 | Word Pattern | [Ruby](./algorithms/ruby/0290-word-pattern.rb) | Easy |

| 295 | Find Median from Data Stream | [Ruby](./algorithms/ruby/0295-find-median-from-data-stream.rb) | Hard |

| 299 | Bulls and Cows | [Ruby](./algorithms/ruby/0299-bulls-and-cows.rb) [Python3](./algorithms/python3/0299-bulls-and-cows.py) | Medium |

| 300 | Longest Increasing Subsequence | [Ruby](./algorithms/ruby/0300-longest-increasing-subsequence.rb) | Medium |

| 316 | Remove Duplicate Letters | [Ruby](./algorithms/ruby/0316-remove-duplicate-letters.rb) | Medium |

| 319 | Bulb Switcher | [Ruby](./algorithms/ruby/0319-bulb-switcher.rb) | Medium |

| 322 | Coin Change | [Ruby](./algorithms/ruby/0322-coin-change.rb) | Medium |

| 328 | Odd Even Linked List | [Ruby](./algorithms/ruby/0328-odd-even-linked-list.rb) | Medium |

| 332 | Reconstruct Itinerary | [Ruby](./algorithms/ruby/0332-reconstruct-itinerary.rb) | Hard |

| 334 | Increasing Triplet Subsequence | [Ruby](./algorithms/ruby/0334-increasing-triplet-subsequence.rb) | Medium |

| 338 | Counting Bits | [Ruby](./algorithms/ruby/0338-counting-bits.rb) | Easy |

| 341 | Flatten Nested List Iterator | [Ruby](./algorithms/ruby/0341-flatten-nested-list-iterator.rb) | Medium |

| 342 | Power of Four | [Ruby](./algorithms/ruby/0342-power-of-four.rb) | Easy |

| 343 | Integer Break | [Ruby](./algorithms/ruby/0343-integer-break.rb) | Medium |

| 344 | Reverse String | [Ruby](./algorithms/ruby/0344-reverse-string.rb) | Easy |

| 345 | Reverse Vowels of a String | [Ruby](./algorithms/ruby/0345-reverse-vowels-of-a-string.rb) | Easy |

| 347 | Top K Frequent Elements | [Ruby](./algorithms/ruby/0347-top-k-frequent-elements.rb) | Medium |

| 373 | Find K Pairs with Smallest Sums | [Ruby](./algorithms/ruby/0373-find-k-pairs-with-smallest-sums.rb) | Medium |

| 374 | Guess Number Higher or Lower | [Ruby](./algorithms/ruby/0374-guess-number-higher-or-lower.rb) | Easy |

| 377 | Combination Sum IV | [Ruby](./algorithms/ruby/0377-combination-sum-iv.rb) | Medium |

| 380 | Insert Delete GetRandom O(1) | [Ruby](./algorithms/ruby/0380-insert-delete-getrandom-o1.rb) | Medium |

| 382 | Linked List Random Node | [Ruby](./algorithms/ruby/0382-linked-list-random-node.rb) | Medium |

| 383 | Ransom Note | [Ruby](./algorithms/ruby/0383-ransom-note.rb) | Easy |

| 387 | First Unique Character in a String | [Ruby](./algorithms/ruby/0387-first-unique-character-in-a-string.rb) | Easy |

| 389 | Find the Difference | [Ruby](./algorithms/ruby/0389-find-the-difference.rb) | Easy |

| 392 | Is Subsequence | [Ruby](./algorithms/ruby/0392-is-subsequence.rb) | Easy |

| 394 | Decode String | [Ruby](./algorithms/ruby/0394-decode-string.rb) | Medium |

| 399 | Evaluate Division | [Ruby](./algorithms/ruby/0399-evaluate-division.rb) | Medium |

| 403 | Frog Jump | [Ruby](./algorithms/ruby/0403-frog-jump.rb) | Hard |

| 409 | Longest Palindrome | [Ruby](./algorithms/ruby/0409-longest-palindrome.rb) | Easy |

| 416 | Partition Equal Subset Sum | [Ruby](./algorithms/ruby/0416-partition-equal-subset-sum.rb) | Medium |

| 417 | Pacific Atlantic Water Flow | [Ruby](./algorithms/ruby/0417-pacific-atlantic-water-flow.rb) | Medium |

| 424 | Longest Repeating Character Replacement | [Ruby](./algorithms/ruby/0424-longest-repeating-character-replacement.rb) | Medium |

| 427 | Construct Quad Tree | [Ruby](./algorithms/ruby/0427-construct-quad-tree.rb) | Medium |

| 432 | All O`one Data Structure | [Ruby](./algorithms/ruby/0432-all-oone-data-structure.rb) | Hard |

| 433 | Minimum Genetic Mutation | [Ruby](./algorithms/ruby/0433-minimum-genetic-mutation.rb) | Medium |

| 435 | Non-overlapping Intervals | [Ruby](./algorithms/ruby/0435-non-overlapping-intervals.rb) | Medium |

| 437 | Path Sum III | [Ruby](./algorithms/ruby/0437-path-sum-iii.rb) | Medium |

| 438 | Find All Anagrams in a String | [Ruby](./algorithms/ruby/0438-find-all-anagrams-in-a-string.rb) | Medium |

| 443 | String Compression | [Ruby](./algorithms/ruby/0443-string-compression.rb) [Python3](./algorithms/python3/0443-string-compression.py) | Medium |

| 445 | Add Two Numbers II | [Ruby](./algorithms/ruby/0445-add-two-numbers-ii.rb) | Medium |

| 450 | Delete Node in a BST | [Ruby](./algorithms/ruby/0450-delete-node-in-a-bst.rb) | Medium |

| 452 | Minimum Number of Arrows to Burst Balloons | [Ruby](./algorithms/ruby/0452-minimum-number-of-arrows-to-burst-balloons.rb) | Medium |

| 455 | Assign Cookies | [Ruby](./algorithms/ruby/0455-assign-cookies.rb) | Easy |

| 456 | 132 Pattern | [Ruby](./algorithms/ruby/0456-132-pattern.rb) | Medium |

| 458 | Poor Pigs | [Ruby](./algorithms/ruby/0458-poor-pigs.rb) | Hard |

| 459 | Repeated Substring Pattern | [Ruby](./algorithms/ruby/0459-repeated-substring-pattern.rb) | Easy |

| 486 | Predict the Winner | [Ruby](./algorithms/ruby/0486-predict-the-winner.rb) | Medium |

| 501 | Find Mode in Binary Search Tree | [Ruby](./algorithms/ruby/0501-find-mode-in-binary-search-tree.rb) | Easy |

| 502 | IPO | [Ruby](./algorithms/ruby/0502-ipo.rb) [Python3](./algorithms/python3/0502-ipo.py) | Hard |

| 509 | Fibonacci Number | [Ruby](./algorithms/ruby/0509-fibonacci-number.rb) | Easy |

| 515 | Find Largest Value in Each Tree Row | [Ruby](./algorithms/ruby/0515-find-largest-value-in-each-tree-row.rb) | Medium |

| 516 | Longest Palindromic Subsequence | [Ruby](./algorithms/ruby/0516-longest-palindromic-subsequence.rb) | Medium |

| 518 | Coin Change II | [Ruby](./algorithms/ruby/0518-coin-change-ii.rb) | Medium |

| 530 | Minimum Absolute Difference in BST | [Ruby](./algorithms/ruby/0530-minimum-absolute-difference-in-bst.rb) | Easy |

| 539 | Minimum Time Difference | [Ruby](./algorithms/ruby/0539-minimum-time-difference.rb) | Medium |

| 540 | Single Element in a Sorted Array | [Ruby](./algorithms/ruby/0540-single-element-in-a-sorted-array.rb) | Medium |

| 542 | 01 Matrix | [Ruby](./algorithms/ruby/0542-01-matrix.rb) | Medium |

| 543 | Diameter of Binary Tree | [Ruby](./algorithms/ruby/0543-diameter-of-binary-tree.rb) | Easy |

| 547 | Number of Provinces | [Ruby](./algorithms/ruby/0547-number-of-provinces.rb) | Medium |

| 557 | Reverse Words in a String III | [Ruby](./algorithms/ruby/0557-reverse-words-in-a-string-iii.rb) | Easy |

| 567 | Permutation in String | [Ruby](./algorithms/ruby/0567-permutation-in-string.rb) | Medium |

| 589 | N-ary Tree Preorder Traversal | [Ruby](./algorithms/ruby/0589-n-ary-tree-preorder-traversal.rb) | Easy |

| 605 | Can Place Flowers | [Ruby](./algorithms/ruby/0605-can-place-flowers.rb) | Easy |

| 606 | Construct String from Binary Tree | [Ruby](./algorithms/ruby/0606-construct-string-from-binary-tree.rb) | Easy |

| 621 | Task Scheduler | [Ruby](./algorithms/ruby/0621-task-scheduler.rb) | Medium |

| 622 | Design Circular Queue | [Ruby](./algorithms/ruby/0622-design-circular-queue.rb) | Medium |

| 624 | Maximum Distance in Arrays | [Ruby](./algorithms/ruby/0624-maximum-distance-in-arrays.rb) | Medium |

| 637 | Average of Levels in Binary Tree | [Ruby](./algorithms/ruby/0637-average-of-levels-in-binary-tree.rb) | Easy |

| 643 | Maximum Average Subarray I | [Ruby](./algorithms/ruby/0643-maximum-average-subarray-i.rb) | Easy |

| 646 | Maximum Length of Pair Chain | [Ruby](./algorithms/ruby/0646-maximum-length-of-pair-chain.rb) | Medium |

| 649 | Dota2 Senate | [Ruby](./algorithms/ruby/0649-dota2-senate.rb) | Medium |

| 652 | Find Duplicate Subtrees | [Ruby](./algorithms/ruby/0652-find-duplicate-subtrees.rb) | Medium |

| 661 | Image Smoother | [Ruby](./algorithms/ruby/0661-image-smoother.rb) | Easy |

| 662 | Maximum Width of Binary Tree | [Ruby](./algorithms/ruby/0662-maximum-width-of-binary-tree.rb) | Medium |

| 664 | Strange Printer | [Ruby](./algorithms/ruby/0664-strange-printer.rb) | Hard |

| 670 | Maximum Swap | [Ruby](./algorithms/ruby/0670-maximum-swap.rb) | Medium |

| 673 | Number of Longest Increasing Subsequence | [Ruby](./algorithms/ruby/0673-number-of-longest-increasing-subsequence.rb) | Medium |

| 688 | Knight Probability in Chessboard | [Ruby](./algorithms/ruby/0688-knight-probability-in-chessboard.rb) | Medium |

| 692 | Top K Frequent Words | [Ruby](./algorithms/ruby/0692-top-k-frequent-words.rb) | Medium |

| 700 | Search in a Binary Search Tree | [Ruby](./algorithms/ruby/0700-search-in-a-binary-search-tree.rb) | Easy |

| 703 | Kth Largest Element in a Stream | [Ruby](./algorithms/ruby/0703-kth-largest-element-in-a-stream.rb) | Easy |

| 704 | Binary Search | [Ruby](./algorithms/ruby/0704-binary-search.rb) | Easy |

| 705 | Design HashSet | [Ruby](./algorithms/ruby/0705-design-hashset.rb) | Easy |

| 706 | Design HashMap | [Ruby](./algorithms/ruby/0706-design-hashmap.rb) | Easy |

| 712 | Minimum ASCII Delete Sum for Two Strings | [Ruby](./algorithms/ruby/0712-minimum-ascii-delete-sum-for-two-strings.rb) | Medium |

| 714 | Best Time to Buy and Sell Stock with Transaction | [Ruby](./algorithms/ruby/0714-best-time-to-buy-and-sell-stock-with-transaction-fee.rb) | Medium |

| 724 | Find Pivot Index | [Ruby](./algorithms/ruby/0724-find-pivot-index.rb) | Easy |

| 725 | Split Linked List in Parts | [Ruby](./algorithms/ruby/0725-split-linked-list-in-parts.rb) | Medium |

| 733 | Flood Fill | [Ruby](./algorithms/ruby/0733-flood-fill.rb) | Easy |

| 735 | Asteroid Collision | [Ruby](./algorithms/ruby/0735-asteroid-collision.rb) | Medium |

| 739 | Daily Temperatures | [Ruby](./algorithms/ruby/0739-daily-temperatures.rb) | Medium |

| 744 | Find Smallest Letter Greater Than Target | [Ruby](./algorithms/ruby/0744-find-smallest-letter-greater-than-target.rb) | Easy |

| 746 | Min Cost Climbing Stairs | [Ruby](./algorithms/ruby/0746-min-cost-climbing-stairs.rb) | Easy |

| 767 | Reorganize String | [Ruby](./algorithms/ruby/0767-reorganize-string.rb) | Medium |

| 779 | K-th Symbol in Grammar | [Ruby](./algorithms/ruby/0779-k-th-symbol-in-grammar.rb) | Medium |

| 783 | Minimum Distance Between BST Nodes | [Ruby](./algorithms/ruby/0783-minimum-distance-between-bst-nodes.rb) [Python3](./algorithms/python3/0783-minimum-distance-between-bst-nodes.py) | Easy |

| 785 | Is Graph Bipartite? | [Ruby](./algorithms/ruby/0785-is-graph-bipartite.rb) | Medium |

| 790 | Domino and Tromino Tiling | [Ruby](./algorithms/ruby/0790-domino-and-tromino-tiling.rb) | Medium |

| 799 | Champagne Tower | [Ruby](./algorithms/ruby/0799-champagne-tower.rb) | Medium |

| 802 | Find Eventual Safe States | [Ruby](./algorithms/ruby/0802-find-eventual-safe-states.rb) | Medium |

| 808 | Soup Servings | [Ruby](./algorithms/python3/0808-soup-servings.py) | Medium |

| 815 | Bus Routes | [Ruby](./algorithms/ruby/0815-bus-routes.rb) | Hard |

| 823 | Binary Trees With Factors | [Ruby](./algorithms/ruby/0823-binary-trees-with-factors.rb) | Medium |

| 837 | New 21 Game | [Ruby](./algorithms/ruby/0837-new-21-game.rb) | Medium |

| 839 | Similar String Groups | [Ruby](./algorithms/ruby/0839-similar-string-groups.rb) | Hard |

| 841 | Backspace String Compare | [Ruby](./algorithms/ruby/0841-keys-and-rooms.rb) | Medium |

| 844 | Backspace String Compare | [Ruby](./algorithms/ruby/0844-backspace-string-compare.rb) | Easy |

| 847 | Shortest Path Visiting All Nodes | [Ruby](./algorithms/ruby/0847-shortest-path-visiting-all-nodes.rb) | Hard |

| 852 | Peak Index in a Mountain Array | [Ruby](./algorithms/ruby/0852-peak-index-in-a-mountain-array.rb) | Medium |

| 859 | Buddy Strings | [Ruby](./algorithms/ruby/0859-buddy-strings.rb) | Easy |

| 863 | All Nodes Distance K in Binary Tree | [Ruby](./algorithms/ruby/0863-all-nodes-distance-k-in-binary-tree.rb) | Medium |

| 864 | Backspace String Compare | [Ruby](./algorithms/ruby/0864-shortest-path-to-get-all-keys.rb) | Hard |

| 867 | Transpose Matrix | [Ruby](./algorithms/ruby/0867-transpose-matrix.rb) | Easy |

| 872 | Leaf-Similar Trees | [Ruby](./algorithms/ruby/0872-leaf-similar-trees.rb) | Medium |

| 875 | Koko Eating Bananas | [Ruby](./algorithms/ruby/0875-koko-eating-bananas.rb) [Python3](./algorithms/python3/0875-koko-eating-bananas.py) | Medium |

| 876 | Middle of the Linked List | [Ruby](./algorithms/ruby/0876-middle-of-the-linked-list.rb) | Easy |

| 879 | Profitable Schemes | [Ruby](./algorithms/ruby/0879-profitable-schemes.rb) | Hard |

| 880 | Decoded String at Index | [Ruby](./algorithms/ruby/0880-decoded-string-at-index.rb) | Medium |

| 881 | Middle of the Linked List | [Ruby](./algorithms/ruby/0881-boats-to-save-people.rb) | Medium |

| 884 | Uncommon Words from Two Sentences | [Ruby](./algorithms/ruby/0884-uncommon-words-from-two-sentences.rb) | Easy |

| 894 | All Possible Full Binary Trees | [Ruby](./algorithms/ruby/0894-all-possible-full-binary-trees.rb) | Medium |

| 896 | Monotonic Array | [Ruby](./algorithms/ruby/0896-monotonic-array.rb) | Easy |

| 901 | Online Stock Span | [Ruby](./algorithms/ruby/0901-online-stock-span.rb) | Medium |

| 904 | Fruit Into Baskets | [Ruby](./algorithms/ruby/0904-fruit-into-baskets.rb) | Medium |

| 905 | Sort Array By Parity | [Ruby](./algorithms/ruby/0905-sort-array-by-parity.rb) | Easy |

| 909 | Snakes and Ladders | [Ruby](./algorithms/ruby/0909-snakes-and-ladders.rb) | Medium |

| 912 | Sort an Array | [Ruby](./algorithms/ruby/0912-sort-an-array.rb) | Medium |

| 918 | Maximum Sum Circular Subarray | [Ruby](./algorithms/ruby/0918-maximum-sum-circular-subarray.rb) | Medium |

| 920 | Number of Music Playlists | [Ruby](./algorithms/ruby/0920-number-of-music-playlists.rb) | Hard |

| 933 | Number of Recent Calls | [Ruby](./algorithms/ruby/0933-number-of-recent-calls.rb) | Easy |

| 934 | Shortest Bridge | [Ruby](./algorithms/ruby/0934-shortest-bridge.rb) | Medium |

| 935 | Knight Dialer | [Ruby](./algorithms/ruby/0935-knight-dialer.rb) | Medium |

| 946 | Validate Stack Sequences | [Ruby](./algorithms/ruby/0946-validate-stack-sequences.rb) | Medium |

| 947 | Most Stones Removed with Same Row or Column | [Ruby](./algorithms/ruby/0947-most-stones-removed-with-same-row-or-column.rb) | Medium |

| 953 | Verifying an Alien Dictionary | [Ruby](./algorithms/ruby/0953-verifying-an-alien-dictionary.rb) | Easy |

| 956 | Tallest Billboard | [Ruby](./algorithms/ruby/0956-tallest-billboard.rb) | Hard |

| 958 | Check Completeness of a Binary Tree | [Ruby](./algorithms/ruby/0958-check-completeness-of-a-binary-tree.rb) | Medium |

| 983 | Minimum Cost For Tickets | [Ruby](./algorithms/ruby/0983-minimum-cost-for-tickets.rb) | Medium |

| 989 | Add to Array-Form of Integer | [Ruby](./algorithms/ruby/0989-add-to-array-form-of-integer.rb) | Easy |

| 990 | Satisfiability of Equality Equations | [Ruby](./algorithms/ruby/0990-satisfiability-of-equality-equations.rb) | Medium |

| 994 | Rotting Oranges | [Ruby](./algorithms/ruby/0994-rotting-oranges.rb) | Medium |

| 1004 | Max Consecutive Ones III | [Ruby](./algorithms/ruby/1004-max-consecutive-ones-iii.rb) | Medium |

| 1011 | Capacity To Ship Packages Within D Days | [Ruby](./algorithms/ruby/1011-capacity-to-ship-packages-within-d-days.rb) | Medium |

| 1020 | Number of Enclaves | [Ruby](./algorithms/ruby/1020-number-of-enclaves.rb) | Medium |

| 1027 | Longest Arithmetic Subsequence | [Ruby](./algorithms/ruby/1027-longest-arithmetic-subsequence.rb) | Medium |

| 1035 | Uncrossed Lines | [Ruby](./algorithms/ruby/1035-uncrossed-lines.rb) | Medium |

| 1046 | Last Stone Weight | [Ruby](./algorithms/ruby/1046-last-stone-weight.rb) | Easy |

| 1048 | Longest String Chain | [Ruby](./algorithms/ruby/1048-longest-string-chain.rb) | Medium |

| 1071 | Greatest Common Divisor of Strings | [Ruby](./algorithms/ruby/1071-greatest-common-divisor-of-strings.rb) | Easy |

| 1091 | Shortest Path in Binary Matrix | [Ruby](./algorithms/ruby/1091-shortest-path-in-binary-matrix.rb) | Medium |

| 1106 | Parsing A Boolean Expression | [Ruby](./algorithms/ruby/1106-parsing-a-boolean-expression.rb) | Hard |

| 1125 | Smallest Sufficient Team | [Ruby](./algorithms/ruby/1125-smallest-sufficient-team.rb) | Hard |

| 1129 | Shortest Path with Alternating Colors | [Ruby](./algorithms/ruby/1129-shortest-path-with-alternating-colors.rb) | Medium |

| 1137 | N-th Tribonacci Number | [Ruby](./algorithms/ruby/1137-n-th-tribonacci-number.rb) | Easy |

| 1140 | Stone Game II | [Ruby](./algorithms/ruby/1140-stone-game-ii.rb) | Medium |

| 1143 | Longest Common Subsequence | [Ruby](./algorithms/ruby/1143-longest-common-subsequence.rb) | Medium |

| 1146 | Snapshot Array | [Ruby](./algorithms/ruby/1146-snapshot-array.rb) | Medium |

| 1155 | Number of Dice Rolls With Target Sum | [Ruby](./algorithms/ruby/1155-number-of-dice-rolls-with-target-sum.rb) | Medium |

| 1160 | Find Words That Can Be Formed by Characters | [Ruby](./algorithms/ruby/1160-find-words-that-can-be-formed-by-characters.rb) | Easy |

| 1161 | Maximum Level Sum of a Binary Tree | [Ruby](./algorithms/ruby/1161-maximum-level-sum-of-a-binary-tree.rb) | Medium |

| 1162 | As Far from Land as Possible | [Ruby](./algorithms/ruby/1162-as-far-from-land-as-possible.rb) | Medium |

| 1187 | Make Array Strictly Increasing | [Ruby](./algorithms/ruby/1187-make-array-strictly-increasing.rb) | Hard |

| 1203 | Sort Items by Groups Respecting Dependencies | [Ruby](./algorithms/ruby/1203-sort-items-by-groups-respecting-dependencies.rb) | Hard |

| 1207 | Unique Number of Occurrences | [Ruby](./algorithms/ruby/1207-unique-number-of-occurrences.rb) | Easy |

| 1218 | Longest Arithmetic Subsequence of Given Difference | [Ruby](./algorithms/ruby/1218-longest-arithmetic-subsequence-of-given-difference.rb) | Medium |

| 1220 | Count Vowels Permutation | [Ruby](./algorithms/ruby/1220-count-vowels-permutation.rb) | Hard |

| 1232 | Check If It Is a Straight Line | [Ruby](./algorithms/ruby/1232-check-if-it-is-a-straight-line.rb) | Easy |

| 1233 | Remove Sub-Folders from the Filesystem | [Ruby](./algorithms/ruby/1233-remove-sub-folders-from-the-filesystem.rb) | Medium |

| 1239 | Maximum Length of a Concatenated String with Unique Characters | [Ruby](./algorithms/ruby/1239-maximum-length-of-a-concatenated-string-with-unique-characters.rb) | Medium |

| 1254 | Number of Closed Islands | [Ruby](./algorithms/ruby/1254-number-of-closed-islands.rb) | Medium |

| 1266 | Minimum Time Visiting All Points | [Ruby](./algorithms/ruby/1266-minimum-time-visiting-all-points.rb) | Easy |

| 1268 | Search Suggestions System | [Ruby](./algorithms/ruby/1268-search-suggestions-system.rb) | Medium |

| 1269 | Number of Ways to Stay in the Same Place After Some Steps | [Ruby](./algorithms/ruby/1269-number-of-ways-to-stay-in-the-same-place-after-some-steps.rb) | Hard |

| 1277 | Count Square Submatrices with All Ones | [Ruby](./algorithms/ruby/1277-count-square-submatrices-with-all-ones.rb) | Medium |

| 1282 | Group the People Given the Group Size They Belong To | [Ruby](./algorithms/ruby/1282-group-the-people-given-the-group-size-they-belong-to.rb) | Medium |

| 1287 | Element Appearing More Than 25% In Sorted Array | [Ruby](./algorithms/ruby/1287-element-appearing-more-than-25-in-sorted-array.rb) | Easy |

| 1318 | Minimum Flips to Make a OR b Equal to c | [Ruby](./algorithms/ruby/1318-minimum-flips-to-make-a-or-b-equal-to-c.rb) | Medium |

| 1319 | Number of Operations to Make Network Connected | [Ruby](./algorithms/ruby/1319-number-of-operations-to-make-network-connected.rb) | Medium |

| 1326 | Minimum Number of Taps to Open to Water a Garden | [Ruby](./algorithms/ruby/1326-minimum-number-of-taps-to-open-to-water-a-garden.rb) | Hard |

| 1337 | The K Weakest Rows in a Matrix | [Ruby](./algorithms/ruby/1337-the-k-weakest-rows-in-a-matrix.rb) | Easy |

| 1351 | Count Negative Numbers in a Sorted Matrix | [Ruby](./algorithms/ruby/1351-count-negative-numbers-in-a-sorted-matrix.rb) | Easy |

| 1359 | Count All Valid Pickup and Delivery Options | [Ruby](./algorithms/ruby/1359-count-all-valid-pickup-and-delivery-options.rb) | Hard |

| 1372 | Longest ZigZag Path in a Binary Tree | [Ruby](./algorithms/ruby/1372-longest-zigzag-path-in-a-binary-tree.rb) | Medium |

| 1345 | Jump Game IV | [Ruby](./algorithms/ruby/1345-jump-game-iv.rb) | Hard |

| 1361 | Validate Binary Tree Nodes | [Ruby](./algorithms/ruby/1361-validate-binary-tree-nodes.rb) | Medium |

| 1371 | Find the Longest Substring Containing Vowels in Even Counts | [Ruby](./algorithms/ruby/1371-find-the-longest-substring-containing-vowels-in-even-counts.rb) | Medium |

| 1376 | Time Needed to Inform All Employees | [Ruby](./algorithms/ruby/1376-time-needed-to-inform-all-employees.rb) | Medium |

| 1381 | Design a Stack With Increment Operation | [Ruby](./algorithms/ruby/1381-design-a-stack-with-increment-operation.rb) | Medium |

| 1396 | Design Underground System | [Ruby](./algorithms/ruby/1396-design-underground-system.rb) | Medium |

| 1402 | Reducing Dishes | [Ruby](./algorithms/ruby/1402-reducing-dishes.rb) | Hard |

| 1405 | Longest Happy String | [Ruby](./algorithms/ruby/1405-longest-happy-string.rb) | Medium |

| 1406 | Stone Game III | [Ruby](./algorithms/ruby/1406-stone-game-iii.rb) | Hard |

| 1416 | Restore The Array | [Ruby](./algorithms/ruby/1416-restore-the-array.rb) | Hard |

| 1420 | Build Array Where You Can Find The Maximum Exactly K Comparisons | [Ruby](./algorithms/ruby/1420-build-array-where-you-can-find-the-maximum-exactly-k-comparisons.rb) | Hard |

| 1422 | Maximum Score After Splitting a String | [Ruby](./algorithms/ruby/1422-maximum-score-after-splitting-a-string.rb) | Easy |

| 1424 | Diagonal Traverse II | [Ruby](./algorithms/ruby/1424-diagonal-traverse-ii.rb) | Medium |

| 1425 | Constrained Subsequence Sum | [Ruby](./algorithms/ruby/1425-constrained-subsequence-sum.rb.rb) | Hard |

| 1431 | Kids With the Greatest Number of Candies | [Ruby](./algorithms/ruby/1431-kids-with-the-greatest-number-of-candies.rb) | Easy |

| 1436 | 1436. Destination City | [Ruby](./algorithms/ruby/1436-destination-city.rb) | Easy |

| 1441 | Build an Array With Stack Operations | [Ruby](./algorithms/ruby/1441-build-an-array-with-stack-operations.rb) | Medium |

| 1444 | Number of Ways of Cutting a Pizza | [Ruby](./algorithms/ruby/1444-number-of-ways-of-cutting-a-pizza.rb) [Python3](./algorithms/python3/1444-number-of-ways-of-cutting-a-pizza.py) | Hard |

| 1448 | Count Good Nodes in Binary Tree | [Ruby](./algorithms/ruby/1448-count-good-nodes-in-binary-tree.rb) | Medium |

| 1456 | Maximum Number of Vowels in a Substring of Given Length | [Ruby](./algorithms/ruby/1456-maximum-number-of-vowels-in-a-substring-of-given-length.rb) | Medium |

| 1457 | Pseudo-Palindromic Paths in a Binary Tree | [Ruby](./algorithms/ruby/1456-pseudo-palindromic-paths-in-a-binary-tree.rb) | Medium |

| 1458 | Max Dot Product of Two Subsequences | [Ruby](./algorithms/ruby/1458-max-dot-product-of-two-subsequences.rb) | Hard |

| 1464 | Maximum Product of Two Elements in an Array | [Ruby](./algorithms/ruby/1464-maximum-product-of-two-elements-in-an-array.rb) | Easy |

| 1466 | Reorder Routes to Make All Paths Lead to the City Zero | [Ruby](./algorithms/ruby/1466-eorder-routes-to-make-all-paths-lead-to-the-city-zero.rb) | Medium |

| 1470 | Shuffle the Array | [Ruby](./algorithms/ruby/1470-shuffle-the-array.rb) | Easy |

| 1472 | Design Browser History | [Ruby](./algorithms/ruby/1472-design-browser-history.rb) | Medium |

| 1480 | Running Sum of 1d Array | [Ruby](./algorithms/ruby/1480-running-sum-of-1d-array.rb) | Easy |

| 1489 | Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree | [Ruby](./algorithms/ruby/1489-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree.rb) | Hard |

| 1491 | Average Salary Excluding the Minimum and Maximum Salary | [Ruby](./algorithms/ruby/1491-average-salary-excluding-the-minimum-and-maximum-salary.rb) | Easy |

| 1493 | Longest Subarray of 1's After Deleting One Element | [Ruby](./algorithms/ruby/1493-longest-subarray-of-1s-after-deleting-one-element.rb) | Medium |

| 1498 | Number of Subsequences That Satisfy the Given Sum Condition | [Ruby](./algorithms/ruby/1498-number-of-subsequences-that-satisfy-the-given-sum-condition.rb) | Medium |

| 1502 | Can Make Arithmetic Progression From Sequence | [Ruby](./algorithms/ruby/1502-can-make-arithmetic-progression-from-sequence.rb) | Easy |

| 1503 | Last Moment Before All Ants Fall Out of a Plank | [Ruby](./algorithms/ruby/1503-last-moment-before-all-ants-fall-out-of-a-plank.rb) | Medium |

| 1508 | Range Sum of Sorted Subarray Sums | [Ruby](./algorithms/ruby/1508-range-sum-of-sorted-subarray-sums.rb) | Medium |

| 1514 | Path with Maximum Probability | [Ruby](./algorithms/ruby/1514-path-with-maximum-probability.rb) | Medium |

| 1523 | Count Odd Numbers in an Interval Range | [Ruby](./algorithms/ruby/1523-count-odd-numbers-in-an-interval-range.rb) | Easy |

| 1535 | Find the Winner of an Array Game | [Ruby](./algorithms/ruby/1535-find-the-winner-of-an-array-game.rb) | Medium |

| 1539 | Kth Missing Positive Number | [Ruby](./algorithms/ruby/1539-kth-missing-positive-number.rb) | Easy |

| 1545 | Find Kth Bit in Nth Binary String | [Ruby](./algorithms/ruby/1545-find-kth-bit-in-nth-binary-string.rb) | Medium |

| 1547 | Minimum Cost to Cut a Stick | [Ruby](./algorithms/ruby/1547-minimum-cost-to-cut-a-stick.rb) | Hard |

| 1557 | Minimum Number of Vertices to Reach All Nodes | [Ruby](./algorithms/ruby/1557-minimum-number-of-vertices-to-reach-all-nodes.rb) | Medium |

| 1561 | Maximum Number of Coins You Can Get | [Ruby](./algorithms/ruby/1561-maximum-number-of-coins-you-can-get.rb) | Medium |

| 1569 | Number of Ways to Reorder Array to Get Same BST | [Ruby](./algorithms/ruby/1569-number-of-ways-to-reorder-array-to-get-same-bst.rb) | Hard |

| 1572 | Matrix Diagonal Sum | [Ruby](./algorithms/ruby/1572-matrix-diagonal-sum.rb) | Easy |

| 1575 | Count All Possible Routes | [Ruby](./algorithms/ruby/1575-count-all-possible-routes.rb) | Hard |

| 1579 | Remove Max Number of Edges to Keep Graph Fully Traversable | [Ruby](./algorithms/ruby/1579-remove-max-number-of-edges-to-keep-graph-fully-traversable.rb) | Hard |

| 1584 | Min Cost to Connect All Points | [Ruby](./algorithms/ruby/1584-min-cost-to-connect-all-points.rb) | Medium |

| 1601 | Maximum Number of Achievable Transfer Requests | [Ruby](./algorithms/ruby/1601-maximum-number-of-achievable-transfer-requests.rb) | Hard |

| 1603 | Design Parking System | [Ruby](./algorithms/ruby/1603-design-parking-system.rb) | Easy |

| 1611 | Minimum One Bit Operations to Make Integers Zero | [Ruby](./algorithms/ruby/1611-minimum-one-bit-operations-to-make-integers-zero.rb) | Hard |

| 1615 | Maximal Network Rank | [Ruby](./algorithms/ruby/1615-maximal-network-rank.rb) | Medium |

| 1630 | Arithmetic Subarrays | [Ruby](./algorithms/ruby/1630-arithmetic-subarrays.rb) | Medium |

| 1631 | Path With Minimum Effort | [Ruby](./algorithms/ruby/1631-path-with-minimum-effort.rb) | Medium |

| 1637 | Widest Vertical Area Between Two Points Containing No Points | [Ruby](./algorithms/ruby/1637-widest-vertical-area-between-two-points-containing-no-points.rb) | Medium |

| 1639 | Number of Ways to Form a Target String Given a Dictionary | [Ruby](./algorithms/ruby/1639-number-of-ways-to-form-a-target-string-given-a-dictionary.rb) | Hard |

| 1647 | Minimum Deletions to Make Character Frequencies Unique | [Ruby](./algorithms/ruby/1647-minimum-deletions-to-make-character-frequencies-unique.rb) | Medium |

| 1657 | Determine if Two Strings Are Close | [Ruby](./algorithms/ruby/1657-determine-if-two-strings-are-close.rb) | Medium |

| 1658 | Minimum Operations to Reduce X to Zero | [Ruby](./algorithms/ruby/1658-minimum-operations-to-reduce-x-to-zero.rb) | Medium |

| 1662 | Check If Two String Arrays are Equivalent | [Ruby](./algorithms/ruby/1662-check-if-two-string-arrays-are-equivalent.rb) | Easy |

| 1671 | Minimum Number of Removals to Make Mountain Array | [Ruby](./algorithms/ruby/1671-minimum-number-of-removals-to-make-mountain-array.rb) | Hard |

| 1675 | Minimize Deviation in Array | [Ruby](./algorithms/ruby/1675-minimize-deviation-in-array.rb) | Hard |

| 1679 | Max Number of K-Sum Pairs | [Ruby](./algorithms/ruby/1679-max-number-of-k-sum-pairs.rb) | Medium |

| 1680 | Concatenation of Consecutive Binary Numbers | [Ruby](./algorithms/ruby/1680-concatenation-of-consecutive-binary-numbers.rb) | Medium |

| 1685 | Sum of Absolute Differences in a Sorted Array | [Ruby](./algorithms/ruby/1685-sum-of-absolute-differences-in-a-sorted-array.rb) | Medium |

| 1688 | Count of Matches in Tournament | [Ruby](./algorithms/ruby/1688-count-of-matches-in-tournament.rb) | Easy |

| 1697 | Checking Existence of Edge Length Limited Paths | [Ruby](./algorithms/ruby/1697-checking-existence-of-edge-length-limited-paths.rb) | Hard |

| 1706 | Where Will the Ball Fall | [Ruby](./algorithms/ruby/1706-where-will-the-ball-fall.rb) | Medium |

| 1716 | Calculate Money in Leetcode Bank | [Ruby](./algorithms/ruby/1716-calculate-money-in-leetcode-bank.rb) | Easy |

| 1721 | Swapping Nodes in a Linked List | [Ruby](./algorithms/ruby/1721-swapping-nodes-in-a-linked-list.rb) | Medium |

| 1727 | Largest Submatrix With Rearrangements | [Ruby](./algorithms/ruby/1727-largest-submatrix-with-rearrangements.rb) | Medium |

| 1732 | Find the Highest Altitude | [Ruby](./algorithms/ruby/1732-find-the-highest-altitude.rb) | Easy |

| 1743 | Restore the Array From Adjacent Pairs | [Ruby](./algorithms/ruby/1743-restore-the-array-from-adjacent-pairs.rb) | Medium |

| 1751 | Maximum Number of Events That Can Be Attended II | [Ruby](./algorithms/ruby/1751-maximum-number-of-events-that-can-be-attended-ii.rb) | Hard |

| 1759 | Count Number of Homogenous Substrings | [Ruby](./algorithms/ruby/1759-count-number-of-homogenous-substrings.rb) | Medium |

| 1768 | Merge Strings Alternately | [Ruby](./algorithms/ruby/1768-merge-strings-alternately.rb) | Easy |

| 1793 | Maximum Score of a Good Subarray | [Ruby](./algorithms/ruby/1793-maximum-score-of-a-good-subarray.rb) | Hard |

| 1799 | Maximize Score After N Operations | [Ruby](./algorithms/ruby/1799-maximize-score-after-n-operations.rb) | Hard |

| 1802 | Maximum Value at a Given Index in a Bounded Array | [Ruby](./algorithms/ruby/1802-maximum-value-at-a-given-index-in-a-bounded-array.rb) | Medium |

| 1814 | Count Nice Pairs in an Array | [Ruby](./algorithms/ruby/1814-count-nice-pairs-in-an-array.rb) | Medium |

| 1822 | Sign of the Product of an Array | [Ruby](./algorithms/ruby/1822-sign-of-the-product-of-an-array.rb) | Easy |

| 1838 | Frequency of the Most Frequent Element | [Ruby](./algorithms/ruby/1838-frequency-of-the-most-frequent-element.rb) | Medium |

| 1845 | Seat Reservation Manager | [Ruby](./algorithms/ruby/1845-seat-reservation-manager.rb) | Medium |

| 1846 | Maximum Element After Decreasing and Rearranging | [Ruby](./algorithms/ruby/1846-maximum-element-after-decreasing-and-rearranging.rb) | Medium |

| 1857 | Largest Color Value in a Directed Graph | [Ruby](./algorithms/ruby/1857-largest-color-value-in-a-directed-graph.rb) | Hard |

| 1870 | Minimum Speed to Arrive on Time | [Ruby](./algorithms/ruby/1870-minimum-speed-to-arrive-on-time.rb) | Medium |

| 1877 | Minimize Maximum Pair Sum in Array | [Ruby](./algorithms/ruby/1877-minimize-maximum-pair-sum-in-array.rb) | Medium |

| 1887 | Minimize Maximum Pair Sum in Array | [Ruby](./algorithms/ruby/1887-reduction-operations-to-make-the-array-elements-equal.rb) | Medium |

| 1894 | Find the Student that Will Replace the Chalk | [Ruby](./algorithms/ruby/1894-find-the-student-that-will-replace-the-chalk.rb) | Medium |

| 1903 | Largest Odd Number in String | [Ruby](./algorithms/ruby/1903-largest-odd-number-in-string.rb) | Easy |

| 1921 | Eliminate Maximum Number of Monsters | [Ruby](./algorithms/ruby/1921-eliminate-maximum-number-of-monsters.rb) | Medium |

| 1926 | Nearest Exit from Entrance in Maze | [Ruby](./algorithms/ruby/1926-nearest-exit-from-entrance-in-maze.rb) | Medium |

| 1930 | Unique Length-3 Palindromic Subsequences | [Ruby](./algorithms/ruby/1930-unique-length-3-palindromic-subsequences.rb) | Medium |

| 1964 | Find the Longest Valid Obstacle Course at Each Position | [Ruby](./algorithms/ruby/1964-find-the-longest-valid-obstacle-course-at-each-position.rb) | Hard |

| 1970 | Last Day Where You Can Still Cross | [Ruby](./algorithms/ruby/1970-last-day-where-you-can-still-cross.rb) | Hard |

| 1980 | Find Unique Binary String | [Ruby](./algorithms/ruby/1980-find-unique-binary-string.rb) | Medium |

| 2009 | Minimum Number of Operations to Make Array Continuous | [Ruby](./algorithms/ruby/2009-minimum-number-of-operations-to-make-array-continuous.rb) | Hard |

| 2024 | Maximize the Confusion of an Exam | [Ruby](./algorithms/ruby/2024-maximize-the-confusion-of-an-exam.rb) | Medium |

| 2044 | Count Number of Maximum Bitwise-OR Subsets | [Ruby](./algorithms/ruby/2044-count-number-of-maximum-bitwise-or-subsets.rb) | Medium |

| 2050 | Parallel Courses III | [Ruby](./algorithms/ruby/2050-parallel-courses-iii.rb) | Hard |

| 2090 | K Radius Subarray Averages | [Ruby](./algorithms/ruby/2090-k-radius-subarray-averages.rb) | Medium |

| 2095 | Delete the Middle Node of a Linked List | [Ruby](./algorithms/ruby/2095-delete-the-middle-node-of-a-linked-list.rb) | Medium |

| 2101 | Detonate the Maximum Bombs | [Ruby](./algorithms/ruby/2101-detonate-the-maximum-bombs.rb) | Medium |

| 2130 | Maximum Twin Sum of a Linked List | [Ruby](./algorithms/ruby/2130-maximum-twin-sum-of-a-linked-list.rb) | Medium |

| 2131 | Longest Palindrome by Concatenating Two Letter Words | [Ruby](./algorithms/ruby/2131-longest-palindrome-by-concatenating-two-letter-words.rb) | Medium |

| 2140 | Solving Questions With Brainpower | [Ruby](./algorithms/ruby/2140-solving-questions-with-brainpower.rb) | Medium |

| 2141 | Maximum Running Time of N Computers | [Ruby](./algorithms/ruby/2141-maximum-running-time-of-n-computers.rb) | Hard |

| 2147 | Number of Ways to Divide a Long Corridor | [Ruby](./algorithms/ruby/2147-number-of-ways-to-divide-a-long-corridor.rb) | Hard |

| 2187 | Minimum Time to Complete Trips | [Ruby](./algorithms/ruby/2187-minimum-time-to-complete-trips.rb) [Python3](./algorithms/python3/2187-minimum-time-to-complete-trips.py) | Medium |

| 2215 | Find the Difference of Two Arrays | [Ruby](./algorithms/ruby/2215-find-the-difference-of-two-arrays.rb) | Easy |

| 2218 | Maximum Value of K Coins From Piles | [Ruby](./algorithms/ruby/2218-maximum-value-of-k-coins-from-piles.rb) | Hard |

| 2251 | Number of Flowers in Full Bloom | [Ruby](./algorithms/ruby/2251-number-of-flowers-in-full-bloom.rb) | Hard |

| 2264 | Largest 3-Same-Digit Number in String | [Ruby](./algorithms/ruby/2264-largest-3-same-digit-number-in-string.rb) | Easy |

| 2265 | Count Nodes Equal to Average of Subtree | [Ruby](./algorithms/ruby/2265-count-nodes-equal-to-average-of-subtree.rb) | Medium |

| 2272 | Substring With Largest Variance | [Ruby](./algorithms/ruby/2272-substring-with-largest-variance.rb) | Hard |

| 2300 | Successful Pairs of Spells and Potions | [Ruby](./algorithms/ruby/2300-successful-pairs-of-spells-and-potions.rb) | Medium |

| 2305 | Fair Distribution of Cookies | [Ruby](./algorithms/ruby/2305-fair-distribution-of-cookies.rb) | Medium |

| 2316 | Count Unreachable Pairs of Nodes in an Undirected Graph | [Ruby](./algorithms/ruby/2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph.rb) | Medium |

| 2328 | Number of Increasing Paths in a Grid | [Ruby](./algorithms/ruby/2328-number-of-increasing-paths-in-a-grid.rb) | Hard |

| 2336 | Smallest Number in Infinite Set | [Ruby](./algorithms/ruby/2336-smallest-number-in-infinite-set.rb) | Medium |

| 2348 | Number of Zero-Filled Subarrays | [Ruby](./algorithms/ruby/2348-number-of-zero-filled-subarrays.rb) | Medium |

| 2352 | Equal Row and Column Pairs | [Ruby](./algorithms/ruby/2352-equal-row-and-column-pairs.rb) | Medium |

| 2353 | Design a Food Rating System | [Ruby](./algorithms/ruby/2353-design-a-food-rating-system.rb) | Medium |

| 2360 | Longest Cycle in a Graph | [Ruby](./algorithms/ruby/2360-longest-cycle-in-a-graph.rb) | Hard |

| 2366 | Minimum Replacements to Sort the Array | [Ruby](./algorithms/ruby/2366-minimum-replacements-to-sort-the-array.rb) | Hard |

| 2369 | Check if There is a Valid Partition For The Array | [Ruby](./algorithms/ruby/2369-check-if-there-is-a-valid-partition-for-the-array.rb) | Medium |

| 2390 | Removing Stars From a String | [Ruby](./algorithms/ruby/2390-removing-stars-from-a-string.rb) | Medium |

| 2391 | Minimum Amount of Time to Collect Garbage | [Ruby](./algorithms/ruby/2391-minimum-amount-of-time-to-collect-garbage.rb) | Medium |

| 2405 | Count Days Spent Together | [Ruby](./algorithms/ruby/2405-optimal-partition-of-string.rb) | Medium |

| 2409 | Count Days Spent Together | [Ruby](./algorithms/ruby/2409-count-days-spent-together.rb) | Easy |

| 2413 | Smallest Even Multiple | [Ruby](./algorithms/ruby/2413-smallest-even-multiple.rb) | Easy |

| 2433 | Find The Original Array of Prefix Xor | [Ruby](./algorithms/ruby/2433-find-the-original-array-of-prefix-xor.rb) | Medium |

| 2439 | Minimize Maximum of Array | [Ruby](./algorithms/ruby/2439-minimize-maximum-of-array.rb) | Medium |

| 2444 | Count Subarrays With Fixed Bounds | [Ruby](./algorithms/ruby/2444-count-subarrays-with-fixed-bounds.rb) | Hard |

| 2448 | Minimum Cost to Make Array Equal | [Ruby](./algorithms/ruby/2448-minimum-cost-to-make-array-equal.rb) | Hard |

| 2458 | Height of Binary Tree After Subtree Removal Queries | [Ruby](./algorithms/ruby/2458-height-of-binary-tree-after-subtree-removal-queries.rb) | Hard |

| 2462 | Total Cost to Hire K Workers | [Python3](./algorithms/python3/2462-total-cost-to-hire-k-workers.py) | Medium |

| 2463 | Minimum Total Distance Traveled | [Ruby](./algorithms/ruby/2463-minimum-total-distance-traveled.rb) | Hard |

| 2466 | Count Ways To Build Good Strings | [Ruby](./algorithms/ruby/2466-count-ways-to-build-good-strings.rb) | Medium |

| 2477 | Minimum Fuel Cost to Report to the Capital | [Ruby](./algorithms/ruby/2477-minimum-fuel-cost-to-report-to-the-capital.rb) | Medium |

| 2483 | Minimum Penalty for a Shop | [Ruby](./algorithms/ruby/2483-minimum-penalty-for-a-shop.rb) | Medium |

| 2492 | Minimum Score of a Path Between Two Cities | [Ruby](./algorithms/ruby/2492-minimum-score-of-a-path-between-two-cities.rb) | Medium |

| 2501 | Longest Square Streak in an Array | [Ruby](./algorithms/ruby/2501-longest-square-streak-in-an-array.rb) | Medium |

| 2542 | Maximum Subsequence Score | [Ruby](./algorithms/ruby/2542-maximum-subsequence-score.rb) | Medium |

| 2551 | Put Marbles in Bags | [Ruby](./algorithms/ruby/2551-put-marbles-in-bags.rb) | Hard |

| 2583 | Kth Largest Sum in a Binary Tree | [Ruby](./algorithms/ruby/2583-kth-largest-sum-in-a-binary-tree.rb) | Medium |

| 2595 | Number of Even and Odd Bits | [Ruby](./algorithms/ruby/2595-number-of-even-and-odd-bits.rb) | Easy |

| 2616 | Minimize the Maximum Difference of Pairs | [Ruby](./algorithms/ruby/2616-minimize-the-maximum-difference-of-pairs.rb) | Medium |

| 2641 | Cousins in Binary Tree II | [Ruby](./algorithms/ruby/2641-cousins-in-binary-tree-ii.rb) | Medium |

| 2642 | Design Graph With Shortest Path Calculator | [Ruby](./algorithms/ruby/2642-design-graph-with-shortest-path-calculator.rb) | Hard |

| 2684 | Maximum Number of Moves in a Grid | [Ruby](./algorithms/ruby/2684-maximum-number-of-moves-in-a-grid.rb) | Medium |

| 2696 | Minimum String Length After Removing Substrings | [Ruby](./algorithms/ruby/2696-minimum-string-length-after-removing-substrings.rb) | Easy |

| 2697 | Lexicographically Smallest Palindrome | [Ruby](./algorithms/ruby/2697-lexicographically-smallest-palindrome.rb) | Easy |

| 2706 | Buy Two Chocolates | [Ruby](./algorithms/ruby/2706-buy-two-chocolates.rb) | Easy |

| 2707 | Extra Characters in a String | [Ruby](./algorithms/ruby/2707-extra-characters-in-a-string.rb) | Medium |

| 2742 | Painting the Walls | [Ruby](./algorithms/ruby/2742-painting-the-walls.rb) | Hard |

| 2785 | Sort Vowels in a String | [Ruby](./algorithms/ruby/2785-sort-vowels-in-a-string.rb) | Medium |

| 2842 | Difference Between Ones and Zeros in Row and Column | [Ruby](./algorithms/ruby/2842-difference-between-ones-and-zeros-in-row-and-column.rb) | Medium |

| 2849 | Determine if a Cell Is Reachable at a Given Time | [Ruby](./algorithms/ruby/2849-determine-if-a-cell-is-reachable-at-a-given-time) | Medium |

| 2966 | Divide Array Into Arrays With Max Difference | [Ruby](./algorithms/ruby/2966-divide-array-into-arrays-with-max-difference) | Medium |

### Database

| # | Title | Solution | Difficulty |

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

| 175 | Combine Two Tables | [MySQL](./database/0175-combine-two-tables.sql) | Easy |

| 181 | Employees Earning More Than Their Managers | [MySQL](./database/0181-employees-earning-more-than-their-managers.sql) | Easy |

| 182 | Duplicate Emails | [MySQL](./database/0182-duplicate-emails.sql) | Easy |

| 183 | Customers Who Never Order | [MySQL](./database/0183-customers-who-never-order.sql) | Easy |

| 196 | Delete Duplicate Emails | [MySQL](./database/0196-delete-duplicate-emails.sql) | Easy |

| 197 | Rising Temperature | [MySQL](./database/0197-rising-temperature.sql) | Easy |

| 550 | Game Play Analysis IV | [MySQL](./database/0550-game-play-analysis-iv.sql) | Medium |

| 570 | Managers with at Least 5 Direct Reports | [MySQL](./database/0570-managers-with-at-least-5-direct-reports.sql) | Medium |

| 577 | Employee Bonus | [MySQL](./database/0577-employee-bonus.sql) | Easy |

| 584 | Find Customer Referee | [MySQL](./database/0584-find-customer-referee.sql) | Easy |

| 595 | Big Countries | [MySQL](./database/0595-big-countries.sql) | Easy |

| 620 | Not Boring Movies | [MySQL](./database/0620-not-boring-movies.sql) | Easy |

| 1068 | Product Sales Analysis I | [Ruby](./database/1068-product-sales-analysis-i.sql) | Easy |

| 1075 | Project Employees I | [Ruby](./database/1075-project-employees-i.sql) | Easy |

| 1148 | Article Views I | [MySQL](./database/1148-article-views-i.sql) | Easy |

| 1174 | Immediate Food Delivery II | [MySQL](./database/1174-immediate-food-delivery-ii.sql) | Medium |

| 1193 | Monthly Transactions I | [MySQL](./database/1193-monthly-transactions-i.sql) | Medium |

| 1211 | Queries Quality and Percentage | [MySQL](./database/1211-queries-quality-and-percentage.sql) | Easy |

| 1251 | Average Selling Price | [MySQL](./database/1251-average-selling-price.sql) | Easy |

| 1280 | Students and Examinations | [MySQL](./database/1280-students-and-examinations.sql) | Easy |

| 1378 | Replace Employee ID With The Unique Identifier | [MySQL](./database/1378-replace-employee-id-with-the-unique-identifier.sql) | Easy |

| 1581 | Customer Who Visited but Did Not Make Any Transactions | [MySQL](./database/1581-customer-who-visited-but-did-not-make-any-transactions.sql) | Easy |

| 1633 | Percentage of Users Attended a Contest | [MySQL](./database/1633-percentage-of-users-attended-a-contest.sql) | Easy |

| 1661 | Average Time of Process per Machine | [MySQL](./database/1661-average-time-of-process-per-machine.sql) | Easy |

| 1683 | Invalid Tweets | [MySQL](./database/1683-invalid-tweets.sql) | Easy |

| 1757 | Recyclable and Low Fat Products | [MySQL](./database/1757-recyclable-and-low-fat-products.sql) | Easy |

| 1934 | Confirmation Rate | [MySQL](./database/1934-confirmation-rate.sql) | Medium |

| 2356 | Confirmation Rate | [MySQL](./database/2356-number-of-unique-subjects-taught-by-each-teacher.sql) | Easy |

### Shell

| # | Title | Solution | Difficulty |

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

| 192 | Word Frequency | [Shell](./shell/0192-word-frequency.sh) | Medium |

| 193 | Valid Phone Numbers | [Shell](./shell/0192-word-frequency.sh) | Easy |

| 194 | Transpose File | [Shell](./shell/0194-transpose-file.sh) | Medium |

| 195 | Tenth Line | [Shell](./shell/0195-tenth-line.sh) | Easy |