| # | Title | Solution | Difficulty |
|---|---|---|---|
| 1 | Two Sum | Ruby | Easy |
| 2 | Add Two Numbers | Ruby | Medium |
| 3 | Longest Substring Without Repeating Characters | Ruby | Medium |
| 4 | Median of Two Sorted Arrays | Ruby | Hard |
| 5 | Longest Palindromic Substring | Ruby | Medium |
| 6 | Verifying an Alien Dictionary | Ruby | Medium |
| 7 | Reverse Integer | Ruby | Medium |
| 8 | String to Integer (atoi) | Ruby | Medium |
| 9 | Palindrome Number | Ruby | Easy |
| 10 | Regular Expression Matching | Ruby | Hard |
| 11 | Container With Most Water | Ruby | Medium |
| 12 | Integer to Roman | Ruby | Medium |
| 13 | Roman to Integer | Ruby | Easy |
| 14 | Longest Common Prefix | Ruby | Easy |
| 15 | 3Sum | Ruby | Medium |
| 16 | 3Sum Closest | Ruby | Medium |
| 17 | Letter Combinations of a Phone Number | Ruby | Medium |
| 18 | 4Sum | Ruby | Medium |
| 19 | Remove Nth Node From End of List | Ruby | Medium |
| 20 | Valid Parentheses | Ruby | Easy |
| 21 | Merge Two Sorted Lists | Ruby | Easy |
| 22 | Generate Parentheses | Ruby | Medium |
| 23 | Merge k Sorted Lists | Ruby | Hard |
| 24 | Swap Nodes in Pairs | Ruby | Medium |
| 25 | Reverse Nodes in k-Group | Ruby | Hard |
| 26 | Remove Duplicates from Sorted Array | Ruby | Easy |
| 27 | Remove Element | Ruby | Easy |
| 28 | Find the Index of the First Occurrence in a String | Ruby | Medium |
| 30 | Substring with Concatenation of All Words | Ruby | Hard |
| 33 | Search in Rotated Sorted Array | Ruby | Medium |
| 34 | Find First and Last Position of Element in Sorted Array | Ruby | Medium |
| 35 | Search Insert Position | Ruby | Easy |
| 36 | Valid Sudoku | Ruby | Medium |
| 39 | Combination Sum | Ruby | Medium |
| 40 | Combination Sum II | Ruby | Medium |
| 42 | Trapping Rain Water | Ruby | Hard |
| 43 | Multiply Strings | Ruby | Medium |
| 45 | Jump Game II | Ruby | Medium |
| 46 | Permutations | Ruby | Medium |
| 48 | Rotate Image | Ruby | Medium |
| 49 | Group Anagrams | Ruby | Medium |
| 50 | Pow(x, n) | Ruby | Medium |
| 52 | N-Queens II | Ruby | Hard |
| 53 | Maximum Subarray | Ruby | Medium |
| 54 | Spiral Matrix | Ruby | Medium |
| 55 | Jump Game | Ruby | Medium |
| 58 | Length of Last Word | Ruby | Easy |
| 59 | Spiral Matrix II | Ruby | Medium |
| 61 | Rotate List | Ruby | Medium |
| 62 | Unique Paths | Ruby | Medium |
| 63 | Unique Paths II | Ruby | Medium |
| 64 | Minimum Path Sum | Ruby | Medium |
| 66 | Plus One | Ruby | Easy |
| 67 | Add Binary | Ruby Python3 | Easy |
| 68 | Text Justification | Ruby | Hard |
| 69 | Sqrt(x) | Ruby | Easy |
| 70 | Climbing Stairs | Ruby | Easy |
| 71 | Climbing Stairs | Ruby | Medium |
| 72 | Edit Distance | Ruby | Hard |
| 73 | Set Matrix Zeroes | Ruby | Medium |
| 74 | Search a 2D Matrix | Ruby | Medium |
| 76 | Minimum Window Substring | Ruby | Hard |
| 77 | Combinations | Ruby | Medium |
| 79 | Word Search | Ruby | Medium |
| 80 | Remove Duplicates from Sorted Array II | Ruby | Medium |
| 81 | Search in Rotated Sorted Array II | Ruby | Medium |
| 82 | Remove Duplicates from Sorted List II | Ruby | Medium |
| 86 | Partition List | Ruby | Medium |
| 87 | Scramble String | Ruby | Hard |
| 88 | Merge Sorted Array | Ruby | Easy |
| 91 | Decode Ways | Ruby | Medium |
| 92 | Reverse Linked List II | Ruby | Medium |
| 94 | Binary Tree Inorder Traversal | Ruby | Easy |
| 95 | Unique Binary Search Trees II | Ruby | Medium |
| 97 | Interleaving String | Ruby | Medium |
| 98 | Validate Binary Search Tree | Ruby | Medium |
| 100 | Same Tree | Ruby | Easy |
| 101 | Symmetric Tree | Ruby | Easy |
| 102 | Binary Tree Level Order Traversal | Ruby | Medium |
| 103 | Binary Tree Zigzag Level Order Traversal | Ruby | Medium |
| 104 | Maximum Depth of Binary Tree | Ruby Python3 | Easy |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | Ruby | Medium |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | Ruby | Medium |
| 108 | Convert Sorted Array to Binary Search Tree | Ruby | Easy |
| 109 | Convert Sorted List to Binary Search Tree | Ruby | Medium |
| 110 | Balanced Binary Tree | Ruby | Easy |
| 111 | Minimum Depth of Binary Tree | Ruby | Easy |
| 112 | Path Sum | Ruby | Easy |
| 113 | Path Sum II | Ruby | Medium |
| 114 | Flatten Binary Tree to Linked List | Ruby | Medium |
| 117 | Populating Next Right Pointers in Each Node II | Ruby | Medium |
| 118 | Pascal's Triangle | Ruby | Easy |
| 119 | Pascal's Triangle II | Ruby | Easy |
| 120 | Triangle | Ruby | Medium |
| 121 | Best Time to Buy and Sell Stock | Ruby | Easy |
| 122 | Best Time to Buy and Sell Stock II | Ruby | Medium |
| 123 | Best Time to Buy and Sell Stock III | Ruby | Hard |
| 124 | Binary Tree Maximum Path Sum | Ruby | Hard |
| 125 | Valid Palindrome | Ruby | Easy |
| 127 | Word Ladder | Ruby | Hard |
| 128 | Longest Consecutive Sequence | Ruby | Medium |
| 129 | Sum Root to Leaf Numbers | Ruby | Medium |
| 130 | Surrounded Regions | Ruby | Medium |
| 133 | Clone Graph | Ruby | Medium |
| 134 | Gas Station | Ruby | Easy |
| 135 | Candy | Ruby | Hard |
| 136 | Single Number | Ruby | Easy |
| 137 | Single Number II | Ruby | Medium |
| 138 | Copy List with Random Pointer | Ruby | Medium |
| 139 | Word Break | Ruby | Medium |
| 141 | Linked List Cycle | Ruby | Easy |
| 142 | Linked List Cycle II | Ruby | Medium |
| 146 | LRU Cache | Ruby | Medium |
| 148 | Sort List | Ruby | Medium |
| 149 | Max Points on a Line | Ruby | Hard |
| 150 | Evaluate Reverse Polish Notation | Ruby | Medium |
| 151 | Reverse Words in a String | Ruby | Medium |
| 152 | Maximum Product Subarray | Ruby | Medium |
| 153 | Find Minimum in Rotated Sorted Array | Ruby | Medium |
| 155 | Min Stack | Ruby | Medium |
| 162 | Find Peak Element | Ruby | Medium |
| 167 | Two Sum II - Input Array Is Sorted | Ruby | Medium |
| 168 | Excel Sheet Column Title | Ruby | Easy |
| 169 | Majority Element | Ruby | Easy |
| 172 | Factorial Trailing Zeroes | Ruby | Medium |
| 173 | Binary Search Tree Iterator | Ruby | Medium |
| 188 | Best Time to Buy and Sell Stock IV | Ruby | Hard |
| 189 | Rotate Array | Ruby | Medium |
| 190 | Reverse Bits | Ruby | Easy |
| 191 | Number of 1 Bits | Ruby | Easy |
| 198 | House Robber | Ruby | Medium |
| 199 | Binary Tree Right Side View | Ruby | Medium |
| 200 | Number of Islands | Ruby | Medium |
| 201 | Bitwise AND of Numbers Range | Ruby | Medium |
| 202 | Happy Number | Ruby | Easy |
| 205 | Isomorphic Strings | Ruby | Easy |
| 206 | Reverse Linked List | Ruby | Easy |
| 207 | Course Schedule | Ruby | Medium |
| 208 | Implement Trie (Prefix Tree) | Ruby | Medium |
| 209 | Minimum Size Subarray Sum | Ruby | Medium |
| 210 | Course Schedule II | Ruby | Medium |
| 211 | Design Add and Search Words Data Structure | Ruby | Medium |
| 212 | Word Search II | Ruby | Hard |
| 215 | Kth Largest Element in an Array | Ruby | Medium |
| 216 | Combination Sum III | Ruby | Medium |
| 219 | Contains Duplicate II | Ruby | Easy |
| 221 | Maximal Square | Ruby | Medium |
| 222 | Count Complete Tree Nodes | Ruby | Medium |
| 224 | Basic Calculator | Ruby | Hard |
| 225 | Implement Stack using Queues | Ruby | Easy |
| 226 | Invert Binary Tree | Ruby | Easy |
| 227 | Basic Calculator II | Ruby | Medium |
| 228 | Summary Ranges | Ruby | Easy |
| 229 | Majority Element II | Ruby | Medium |
| 230 | Kth Smallest Element in a BST | Ruby | Medium |
| 232 | Implement Queue using Stacks | Ruby | Easy |
| 234 | Palindrome Linked List | Ruby | Easy |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Ruby | Medium |
| 236 | Lowest Common Ancestor of a Binary Tree | Ruby | Medium |
| 238 | Product of Array Except Self | Ruby | Medium |
| 239 | Sliding Window Maximum | Ruby | Hard |
| 242 | Valid Anagram | Ruby | Easy |
| 258 | Add Digits | Ruby | Easy |
| 274 | H-Index | Ruby | Medium |
| 278 | First Bad Version | Ruby | Easy |
| 283 | Move Zeroes | Ruby | Easy |
| 287 | Find the Duplicate Number | Ruby | Medium |
| 289 | Game of Life | Ruby | Medium |
| 290 | Word Pattern | Ruby | Easy |
| 295 | Find Median from Data Stream | Ruby | Hard |
| 299 | Bulls and Cows | Ruby Python3 | Medium |
| 300 | Longest Increasing Subsequence | Ruby | Medium |
| 316 | Remove Duplicate Letters | Ruby | Medium |
| 319 | Bulb Switcher | Ruby | Medium |
| 322 | Coin Change | Ruby | Medium |
| 328 | Odd Even Linked List | Ruby | Medium |
| 332 | Reconstruct Itinerary | Ruby | Hard |
| 334 | Increasing Triplet Subsequence | Ruby | Medium |
| 338 | Counting Bits | Ruby | Easy |
| 341 | Flatten Nested List Iterator | Ruby | Medium |
| 342 | Power of Four | Ruby | Easy |
| 343 | Integer Break | Ruby | Medium |
| 344 | Reverse String | Ruby | Easy |
| 345 | Reverse Vowels of a String | Ruby | Easy |
| 347 | Top K Frequent Elements | Ruby | Medium |
| 373 | Find K Pairs with Smallest Sums | Ruby | Medium |
| 374 | Guess Number Higher or Lower | Ruby | Easy |
| 377 | Combination Sum IV | Ruby | Medium |
| 380 | Insert Delete GetRandom O(1) | Ruby | Medium |
| 382 | Linked List Random Node | Ruby | Medium |
| 383 | Ransom Note | Ruby | Easy |
| 387 | First Unique Character in a String | Ruby | Easy |
| 389 | Find the Difference | Ruby | Easy |
| 392 | Is Subsequence | Ruby | Easy |
| 394 | Decode String | Ruby | Medium |
| 399 | Evaluate Division | Ruby | Medium |
| 403 | Frog Jump | Ruby | Hard |
| 409 | Longest Palindrome | Ruby | Easy |
| 416 | Partition Equal Subset Sum | Ruby | Medium |
| 417 | Pacific Atlantic Water Flow | Ruby | Medium |
| 424 | Longest Repeating Character Replacement | Ruby | Medium |
| 427 | Construct Quad Tree | Ruby | Medium |
| 433 | Minimum Genetic Mutation | Ruby | Medium |
| 435 | Non-overlapping Intervals | Ruby | Medium |
| 437 | Path Sum III | Ruby | Medium |
| 438 | Find All Anagrams in a String | Ruby | Medium |
| 443 | String Compression | Ruby Python3 | Medium |
| 445 | Add Two Numbers II | Ruby | Medium |
| 450 | Delete Node in a BST | Ruby | Medium |
| 452 | Minimum Number of Arrows to Burst Balloons | Ruby | Medium |
| 455 | Assign Cookies | Ruby | Easy |
| 456 | 132 Pattern | Ruby | Medium |
| 458 | Poor Pigs | Ruby | Hard |
| 459 | Repeated Substring Pattern | Ruby | Easy |
| 486 | Predict the Winner | Ruby | Medium |
| 501 | Find Mode in Binary Search Tree | Ruby | Easy |
| 502 | IPO | Ruby Python3 | Hard |
| 509 | Fibonacci Number | Ruby | Easy |
| 515 | Find Largest Value in Each Tree Row | Ruby | Medium |
| 516 | Longest Palindromic Subsequence | Ruby | Medium |
| 518 | Coin Change II | Ruby | Medium |
| 530 | Minimum Absolute Difference in BST | Ruby | Easy |
| 540 | Single Element in a Sorted Array | Ruby | Medium |
| 542 | 01 Matrix | Ruby | Medium |
| 543 | Diameter of Binary Tree | Ruby | Easy |
| 547 | Number of Provinces | Ruby | Medium |
| 557 | Reverse Words in a String III | Ruby | Easy |
| 567 | Permutation in String | Ruby | Medium |
| 589 | N-ary Tree Preorder Traversal | Ruby | Easy |
| 605 | Can Place Flowers | Ruby | Easy |
| 606 | Construct String from Binary Tree | Ruby | Easy |
| 621 | Task Scheduler | Ruby | Medium |
| 622 | Design Circular Queue | Ruby | Medium |
| 624 | Maximum Distance in Arrays | Ruby | Medium |
| 637 | Average of Levels in Binary Tree | Ruby | Easy |
| 643 | Maximum Average Subarray I | Ruby | Easy |
| 646 | Maximum Length of Pair Chain | Ruby | Medium |
| 649 | Dota2 Senate | Ruby | Medium |
| 652 | Find Duplicate Subtrees | Ruby | Medium |
| 661 | Image Smoother | Ruby | Easy |
| 662 | Maximum Width of Binary Tree | Ruby | Medium |
| 664 | Strange Printer | Ruby | Hard |
| 673 | Number of Longest Increasing Subsequence | Ruby | Medium |
| 688 | Knight Probability in Chessboard | Ruby | Medium |
| 692 | Top K Frequent Words | Ruby | Medium |
| 700 | Search in a Binary Search Tree | Ruby | Easy |
| 703 | Kth Largest Element in a Stream | Ruby | Easy |
| 704 | Binary Search | Ruby | Easy |
| 705 | Design HashSet | Ruby | Easy |
| 706 | Design HashMap | Ruby | Easy |
| 712 | Minimum ASCII Delete Sum for Two Strings | Ruby | Medium |
| 714 | Best Time to Buy and Sell Stock with Transaction | Ruby | Medium |
| 724 | Find Pivot Index | Ruby | Easy |
| 725 | Split Linked List in Parts | Ruby | Medium |
| 733 | Flood Fill | Ruby | Easy |
| 735 | Asteroid Collision | Ruby | Medium |
| 739 | Daily Temperatures | Ruby | Medium |
| 744 | Find Smallest Letter Greater Than Target | Ruby | Easy |
| 746 | Min Cost Climbing Stairs | Ruby | Easy |
| 767 | Reorganize String | Ruby | Medium |
| 779 | K-th Symbol in Grammar | Ruby | Medium |
| 783 | Minimum Distance Between BST Nodes | Ruby Python3 | Easy |
| 785 | Is Graph Bipartite? | Ruby | Medium |
| 790 | Domino and Tromino Tiling | Ruby | Medium |
| 799 | Champagne Tower | Ruby | Medium |
| 802 | Find Eventual Safe States | Ruby | Medium |
| 808 | Soup Servings | Ruby | Medium |
| 815 | Bus Routes | Ruby | Hard |
| 823 | Binary Trees With Factors | Ruby | Medium |
| 837 | New 21 Game | Ruby | Medium |
| 839 | Similar String Groups | Ruby | Hard |
| 841 | Backspace String Compare | Ruby | Medium |
| 844 | Backspace String Compare | Ruby | Easy |
| 847 | Shortest Path Visiting All Nodes | Ruby | Hard |
| 852 | Peak Index in a Mountain Array | Ruby | Medium |
| 859 | Buddy Strings | Ruby | Easy |
| 863 | All Nodes Distance K in Binary Tree | Ruby | Medium |
| 864 | Backspace String Compare | Ruby | Hard |
| 867 | Transpose Matrix | Ruby | Easy |
| 872 | Leaf-Similar Trees | Ruby | Medium |
| 875 | Koko Eating Bananas | Ruby Python3 | Medium |
| 876 | Middle of the Linked List | Ruby | Easy |
| 879 | Profitable Schemes | Ruby | Hard |
| 880 | Decoded String at Index | Ruby | Medium |
| 881 | Middle of the Linked List | Ruby | Medium |
| 894 | All Possible Full Binary Trees | Ruby | Medium |
| 896 | Monotonic Array | Ruby | Easy |
| 901 | Online Stock Span | Ruby | Medium |
| 904 | Fruit Into Baskets | Ruby | Medium |
| 905 | Sort Array By Parity | Ruby | Easy |
| 909 | Snakes and Ladders | Ruby | Medium |
| 912 | Sort an Array | Ruby | Medium |
| 918 | Maximum Sum Circular Subarray | Ruby | Medium |
| 920 | Number of Music Playlists | Ruby | Hard |
| 933 | Number of Recent Calls | Ruby | Easy |
| 934 | Shortest Bridge | Ruby | Medium |
| 935 | Knight Dialer | Ruby | Medium |
| 946 | Validate Stack Sequences | Ruby | Medium |
| 947 | Most Stones Removed with Same Row or Column | Ruby | Medium |
| 953 | Verifying an Alien Dictionary | Ruby | Easy |
| 956 | Tallest Billboard | Ruby | Hard |
| 958 | Check Completeness of a Binary Tree | Ruby | Medium |
| 983 | Minimum Cost For Tickets | Ruby | Medium |
| 989 | Add to Array-Form of Integer | Ruby | Easy |
| 990 | Satisfiability of Equality Equations | Ruby | Medium |
| 994 | Rotting Oranges | Ruby | Medium |
| 1004 | Max Consecutive Ones III | Ruby | Medium |
| 1011 | Capacity To Ship Packages Within D Days | Ruby | Medium |
| 1020 | Number of Enclaves | Ruby | Medium |
| 1027 | Longest Arithmetic Subsequence | Ruby | Medium |
| 1035 | Uncrossed Lines | Ruby | Medium |
| 1046 | Last Stone Weight | Ruby | Easy |
| 1048 | Longest String Chain | Ruby | Medium |
| 1071 | Greatest Common Divisor of Strings | Ruby | Easy |
| 1091 | Shortest Path in Binary Matrix | Ruby | Medium |
| 1125 | Smallest Sufficient Team | Ruby | Hard |
| 1129 | Shortest Path with Alternating Colors | Ruby | Medium |
| 1137 | N-th Tribonacci Number | Ruby | Easy |
| 1140 | Stone Game II | Ruby | Medium |
| 1143 | Longest Common Subsequence | Ruby | Medium |
| 1146 | Snapshot Array | Ruby | Medium |
| 1155 | Number of Dice Rolls With Target Sum | Ruby | Medium |
| 1160 | Find Words That Can Be Formed by Characters | Ruby | Easy |
| 1161 | Maximum Level Sum of a Binary Tree | Ruby | Medium |
| 1162 | As Far from Land as Possible | Ruby | Medium |
| 1187 | Make Array Strictly Increasing | Ruby | Hard |
| 1203 | Sort Items by Groups Respecting Dependencies | Ruby | Hard |
| 1207 | Unique Number of Occurrences | Ruby | Easy |
| 1218 | Longest Arithmetic Subsequence of Given Difference | Ruby | Medium |
| 1220 | Count Vowels Permutation | Ruby | Hard |
| 1232 | Check If It Is a Straight Line | Ruby | Easy |
| 1239 | Maximum Length of a Concatenated String with Unique Characters | Ruby | Medium |
| 1254 | Number of Closed Islands | Ruby | Medium |
| 1266 | Minimum Time Visiting All Points | Ruby | Easy |
| 1268 | Search Suggestions System | Ruby | Medium |
| 1269 | Number of Ways to Stay in the Same Place After Some Steps | Ruby | Hard |
| 1282 | Group the People Given the Group Size They Belong To | Ruby | Medium |
| 1287 | Element Appearing More Than 25% In Sorted Array | Ruby | Easy |
| 1318 | Minimum Flips to Make a OR b Equal to c | Ruby | Medium |
| 1319 | Number of Operations to Make Network Connected | Ruby | Medium |
| 1326 | Minimum Number of Taps to Open to Water a Garden | Ruby | Hard |
| 1337 | The K Weakest Rows in a Matrix | Ruby | Easy |
| 1351 | Count Negative Numbers in a Sorted Matrix | Ruby | Easy |
| 1359 | Count All Valid Pickup and Delivery Options | Ruby | Hard |
| 1372 | Longest ZigZag Path in a Binary Tree | Ruby | Medium |
| 1345 | Jump Game IV | Ruby | Hard |
| 1361 | Validate Binary Tree Nodes | Ruby | Medium |
| 1376 | Time Needed to Inform All Employees | Ruby | Medium |
| 1396 | Design Underground System | Ruby | Medium |
| 1402 | Reducing Dishes | Ruby | Hard |
| 1406 | Stone Game III | Ruby | Hard |
| 1416 | Restore The Array | Ruby | Hard |
| 1420 | Build Array Where You Can Find The Maximum Exactly K Comparisons | Ruby | Hard |
| 1422 | Maximum Score After Splitting a String | Ruby | Easy |
| 1424 | Diagonal Traverse II | Ruby | Medium |
| 1425 | Constrained Subsequence Sum | Ruby | Hard |
| 1431 | Kids With the Greatest Number of Candies | Ruby | Easy |
| 1436 | 1436. Destination City | Ruby | Easy |
| 1441 | Build an Array With Stack Operations | Ruby | Medium |
| 1444 | Number of Ways of Cutting a Pizza | Ruby Python3 | Hard |
| 1448 | Count Good Nodes in Binary Tree | Ruby | Medium |
| 1456 | Maximum Number of Vowels in a Substring of Given Length | Ruby | Medium |
| 1457 | Pseudo-Palindromic Paths in a Binary Tree | Ruby | Medium |
| 1458 | Max Dot Product of Two Subsequences | Ruby | Hard |
| 1464 | Maximum Product of Two Elements in an Array | Ruby | Easy |
| 1466 | Reorder Routes to Make All Paths Lead to the City Zero | Ruby | Medium |
| 1470 | Shuffle the Array | Ruby | Easy |
| 1472 | Design Browser History | Ruby | Medium |
| 1480 | Running Sum of 1d Array | Ruby | Easy |
| 1489 | Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree | Ruby | Hard |
| 1491 | Average Salary Excluding the Minimum and Maximum Salary | Ruby | Easy |
| 1493 | Longest Subarray of 1's After Deleting One Element | Ruby | Medium |
| 1498 | Number of Subsequences That Satisfy the Given Sum Condition | Ruby | Medium |
| 1502 | Can Make Arithmetic Progression From Sequence | Ruby | Easy |
| 1503 | Last Moment Before All Ants Fall Out of a Plank | Ruby | Medium |
| 1508 | Range Sum of Sorted Subarray Sums | Ruby | Medium |
| 1514 | Path with Maximum Probability | Ruby | Medium |
| 1523 | Count Odd Numbers in an Interval Range | Ruby | Easy |
| 1535 | Find the Winner of an Array Game | Ruby | Medium |
| 1539 | Kth Missing Positive Number | Ruby | Easy |
| 1547 | Minimum Cost to Cut a Stick | Ruby | Hard |
| 1557 | Minimum Number of Vertices to Reach All Nodes | Ruby | Medium |
| 1561 | Maximum Number of Coins You Can Get | Ruby | Medium |
| 1569 | Number of Ways to Reorder Array to Get Same BST | Ruby | Hard |
| 1572 | Matrix Diagonal Sum | Ruby | Easy |
| 1575 | Count All Possible Routes | Ruby | Hard |
| 1579 | Remove Max Number of Edges to Keep Graph Fully Traversable | Ruby | Hard |
| 1584 | Min Cost to Connect All Points | Ruby | Medium |
| 1601 | Maximum Number of Achievable Transfer Requests | Ruby | Hard |
| 1603 | Design Parking System | Ruby | Easy |
| 1611 | Minimum One Bit Operations to Make Integers Zero | Ruby | Hard |
| 1615 | Maximal Network Rank | Ruby | Medium |
| 1630 | Arithmetic Subarrays | Ruby | Medium |
| 1631 | Path With Minimum Effort | Ruby | Medium |
| 1637 | Widest Vertical Area Between Two Points Containing No Points | Ruby | Medium |
| 1639 | Number of Ways to Form a Target String Given a Dictionary | Ruby | Hard |
| 1647 | Minimum Deletions to Make Character Frequencies Unique | Ruby | Medium |
| 1657 | Determine if Two Strings Are Close | Ruby | Medium |
| 1658 | Minimum Operations to Reduce X to Zero | Ruby | Medium |
| 1662 | Check If Two String Arrays are Equivalent | Ruby | Easy |
| 1675 | Minimize Deviation in Array | Ruby | Hard |
| 1679 | Max Number of K-Sum Pairs | Ruby | Medium |
| 1680 | Concatenation of Consecutive Binary Numbers | Ruby | Medium |
| 1685 | Sum of Absolute Differences in a Sorted Array | Ruby | Medium |
| 1688 | Count of Matches in Tournament | Ruby | Easy |
| 1697 | Checking Existence of Edge Length Limited Paths | Ruby | Hard |
| 1706 | Where Will the Ball Fall | Ruby | Medium |
| 1716 | Calculate Money in Leetcode Bank | Ruby | Easy |
| 1721 | Swapping Nodes in a Linked List | Ruby | Medium |
| 1727 | Largest Submatrix With Rearrangements | Ruby | Medium |
| 1732 | Find the Highest Altitude | Ruby | Easy |
| 1743 | Restore the Array From Adjacent Pairs | Ruby | Medium |
| 1751 | Maximum Number of Events That Can Be Attended II | Ruby | Hard |
| 1759 | Count Number of Homogenous Substrings | Ruby | Medium |
| 1768 | Merge Strings Alternately | Ruby | Easy |
| 1793 | Maximum Score of a Good Subarray | Ruby | Hard |
| 1799 | Maximize Score After N Operations | Ruby | Hard |
| 1802 | Maximum Value at a Given Index in a Bounded Array | Ruby | Medium |
| 1814 | Count Nice Pairs in an Array | Ruby | Medium |
| 1822 | Sign of the Product of an Array | Ruby | Easy |
| 1838 | Frequency of the Most Frequent Element | Ruby | Medium |
| 1845 | Seat Reservation Manager | Ruby | Medium |
| 1846 | Maximum Element After Decreasing and Rearranging | Ruby | Medium |
| 1857 | Largest Color Value in a Directed Graph | Ruby | Hard |
| 1870 | Minimum Speed to Arrive on Time | Ruby | Medium |
| 1877 | Minimize Maximum Pair Sum in Array | Ruby | Medium |
| 1887 | Minimize Maximum Pair Sum in Array | Ruby | Medium |
| 1903 | Largest Odd Number in String | Ruby | Easy |
| 1921 | Eliminate Maximum Number of Monsters | Ruby | Medium |
| 1926 | Nearest Exit from Entrance in Maze | Ruby | Medium |
| 1930 | Unique Length-3 Palindromic Subsequences | Ruby | Medium |
| 1964 | Find the Longest Valid Obstacle Course at Each Position | Ruby | Hard |
| 1970 | Last Day Where You Can Still Cross | Ruby | Hard |
| 1980 | Find Unique Binary String | Ruby | Medium |
| 2009 | Minimum Number of Operations to Make Array Continuous | Ruby | Hard |
| 2024 | Maximize the Confusion of an Exam | Ruby | Medium |
| 2050 | Parallel Courses III | Ruby | Hard |
| 2090 | K Radius Subarray Averages | Ruby | Medium |
| 2095 | Delete the Middle Node of a Linked List | Ruby | Medium |
| 2101 | Detonate the Maximum Bombs | Ruby | Medium |
| 2130 | Maximum Twin Sum of a Linked List | Ruby | Medium |
| 2131 | Longest Palindrome by Concatenating Two Letter Words | Ruby | Medium |
| 2140 | Solving Questions With Brainpower | Ruby | Medium |
| 2141 | Maximum Running Time of N Computers | Ruby | Hard |
| 2147 | Number of Ways to Divide a Long Corridor | Ruby | Hard |
| 2187 | Minimum Time to Complete Trips | Ruby Python3 | Medium |
| 2215 | Find the Difference of Two Arrays | Ruby | Easy |
| 2218 | Maximum Value of K Coins From Piles | Ruby | Hard |
| 2251 | Number of Flowers in Full Bloom | Ruby | Hard |
| 2264 | Largest 3-Same-Digit Number in String | Ruby | Easy |
| 2265 | Count Nodes Equal to Average of Subtree | Ruby | Medium |
| 2272 | Substring With Largest Variance | Ruby | Hard |
| 2300 | Successful Pairs of Spells and Potions | Ruby | Medium |
| 2305 | Fair Distribution of Cookies | Ruby | Medium |
| 2316 | Count Unreachable Pairs of Nodes in an Undirected Graph | Ruby | Medium |
| 2328 | Number of Increasing Paths in a Grid | Ruby | Hard |
| 2336 | Smallest Number in Infinite Set | Ruby | Medium |
| 2348 | Number of Zero-Filled Subarrays | Ruby | Medium |
| 2352 | Equal Row and Column Pairs | Ruby | Medium |
| 2353 | Design a Food Rating System | Ruby | Medium |
| 2360 | Longest Cycle in a Graph | Ruby | Hard |
| 2366 | Minimum Replacements to Sort the Array | Ruby | Hard |
| 2369 | Check if There is a Valid Partition For The Array | Ruby | Medium |
| 2390 | Removing Stars From a String | Ruby | Medium |
| 2391 | Minimum Amount of Time to Collect Garbage | Ruby | Medium |
| 2405 | Count Days Spent Together | Ruby | Medium |
| 2409 | Count Days Spent Together | Ruby | Easy |
| 2413 | Smallest Even Multiple | Ruby | Easy |
| 2433 | Find The Original Array of Prefix Xor | Ruby | Medium |
| 2439 | Minimize Maximum of Array | Ruby | Medium |
| 2444 | Count Subarrays With Fixed Bounds | Ruby | Hard |
| 2448 | Minimum Cost to Make Array Equal | Ruby | Hard |
| 2462 | Total Cost to Hire K Workers | Python3 | Medium |
| 2466 | Count Ways To Build Good Strings | Ruby | Medium |
| 2477 | Minimum Fuel Cost to Report to the Capital | Ruby | Medium |
| 2483 | Minimum Penalty for a Shop | Ruby | Medium |
| 2492 | Minimum Score of a Path Between Two Cities | Ruby | Medium |
| 2542 | Maximum Subsequence Score | Ruby | Medium |
| 2551 | Put Marbles in Bags | Ruby | Hard |
| 2595 | Number of Even and Odd Bits | Ruby | Easy |
| 2616 | Minimize the Maximum Difference of Pairs | Ruby | Medium |
| 2642 | Design Graph With Shortest Path Calculator | Ruby | Hard |
| 2696 | Minimum String Length After Removing Substrings | Ruby | Easy |
| 2697 | Lexicographically Smallest Palindrome | Ruby | Easy |
| 2706 | Buy Two Chocolates | Ruby | Easy |
| 2707 | Extra Characters in a String | Ruby | Medium |
| 2742 | Painting the Walls | Ruby | Hard |
| 2785 | Sort Vowels in a String | Ruby | Medium |
| 2842 | Difference Between Ones and Zeros in Row and Column | Ruby | Medium |
| 2849 | Determine if a Cell Is Reachable at a Given Time | Ruby | Medium |
| 2966 | Divide Array Into Arrays With Max Difference | Ruby | Medium |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 175 | Combine Two Tables | MySQL | Easy |
| 181 | Employees Earning More Than Their Managers | MySQL | Easy |
| 182 | Duplicate Emails | MySQL | Easy |
| 183 | Customers Who Never Order | MySQL | Easy |
| 196 | Delete Duplicate Emails | MySQL | Easy |
| 197 | Rising Temperature | MySQL | Easy |
| 550 | Game Play Analysis IV | MySQL | Medium |
| 570 | Managers with at Least 5 Direct Reports | MySQL | Medium |
| 577 | Employee Bonus | MySQL | Easy |
| 584 | Find Customer Referee | MySQL | Easy |
| 595 | Big Countries | MySQL | Easy |
| 620 | Not Boring Movies | MySQL | Easy |
| 1068 | Product Sales Analysis I | Ruby | Easy |
| 1075 | Project Employees I | Ruby | Easy |
| 1148 | Article Views I | MySQL | Easy |
| 1174 | Immediate Food Delivery II | MySQL | Medium |
| 1193 | Monthly Transactions I | MySQL | Medium |
| 1211 | Queries Quality and Percentage | MySQL | Easy |
| 1251 | Average Selling Price | MySQL | Easy |
| 1280 | Students and Examinations | MySQL | Easy |
| 1378 | Replace Employee ID With The Unique Identifier | MySQL | Easy |
| 1581 | Customer Who Visited but Did Not Make Any Transactions | MySQL | Easy |
| 1633 | Percentage of Users Attended a Contest | MySQL | Easy |
| 1661 | Average Time of Process per Machine | MySQL | Easy |
| 1683 | Invalid Tweets | MySQL | Easy |
| 1757 | Recyclable and Low Fat Products | MySQL | Easy |
| 1934 | Confirmation Rate | MySQL | Medium |
| 2356 | Confirmation Rate | MySQL | Easy |
| # | Title | Solution | Difficulty |
|---|---|---|---|
| 192 | Word Frequency | Shell | Medium |
| 193 | Valid Phone Numbers | Shell | Easy |
| 194 | Transpose File | Shell | Medium |
| 195 | Tenth Line | Shell | Easy |