A collection of LeetCode problems implemented in Python with detailed complexity analysis and explanations.
| # | Problem | Difficulty | Pattern | Time | Space |
|---|---|---|---|---|---|
| 1 | Two Sum | Easy | Hash Map | O(n) | O(n) |
| 2 | Add Two Numbers | Medium | Two Pointers | O(n) | O(1) |
| 3 | Longest Substring Without Repeating Characters | Medium | Sliding Window | O(n) | O(1) |
| 4 | Median of Two Sorted Arrays | Hard | Binary Search | O(n) | O(1) |
| 5 | Longest Palindromic Substring | Medium | Array / General | O(n) | O(1) |
| 6 | Zigzag Conversion | Medium | Array / General | O(n) | O(1) |
| 8 | String to Integer (atoi) | Medium | Bit Manipulation | O(n) | O(1) |
| 9 | Palindrome Number | Easy | Two Pointers | O(n) | O(1) |
| 13 | Roman to Integer | Easy | Prefix Sum | O(n) | O(n) |
| 14 | Longest Common Prefix | Easy | Prefix Sum | O(n) | O(n) |
| 21 | Merge Two Sorted Lists | Easy | Two Pointers | O(n) | O(1) |
| 23 | Merge k Sorted Lists | Hard | Two Pointers | O(n) | O(1) |
| 24 | Swap Nodes in Pairs | Medium | Two Pointers | O(n) | O(1) |
| 25 | Reverse Nodes in k-Group | Hard | Two Pointers | O(n) | O(1) |
| 26 | Remove Duplicates from Sorted Array | Easy | Array / General | O(n) | O(1) |
| 27 | Remove Element | Easy | Array / General | O(n) | O(1) |
| 28 | Find the Index of the First Occurrence in a String | Easy | Stack & Queue | O(n) | O(n) |
| 29 | Divide Two Integers | Medium | Bit Manipulation | O(n) | O(1) |
| 30 | Substring with Concatenation of All Words | Hard | Sliding Window | O(n) | O(1) |
| 31 | Next Permutation | Medium | Backtracking | O(n) | O(1) |
| 32 | Longest Valid Parentheses | Hard | Stack & Queue | O(n) | O(n) |
| 34 | Find First and Last Position of Element in Sorted Array | Medium | Binary Search | O(log n) | O(1) |
| 35 | Search Insert Position | Easy | Binary Search | O(log n) | O(1) |
| 36 | Valid Sudoku | Medium | Array / General | O(n) | O(1) |
| 37 | Sudoku Solver | Hard | Array / General | O(n) | O(1) |
| 38 | Count and Say | Medium | Tree & Graph | O(n) | O(n) |
| 39 | Combination Sum | Medium | Backtracking | O(n) | O(1) |
| 40 | Combination Sum II | Medium | Backtracking | O(n) | O(1) |
| 41 | First Missing Positive | Hard | Array / General | O(n) | O(1) |
| 42 | Trapping Rain Water | Hard | Array / General | O(n) | O(1) |
| 43 | Multiply Strings | Medium | Array / General | O(n) | O(1) |
| 44 | Wildcard Matching | Hard | Array / General | O(n) | O(1) |
| 45 | Jump Game II | Medium | Array / General | O(n) | O(1) |
| 46 | Permutations | Medium | Backtracking | O(n) | O(1) |
| 47 | Permutations II | Medium | Backtracking | O(n) | O(1) |
| 49 | Group Anagrams | Medium | Hash Map | O(n) | O(n) |
| 50 | Pow(x, n) | Medium | Tree & Graph | O(n) | O(n) |
| 51 | N-Queens | Hard | Tree & Graph | O(n) | O(n) |
| 52 | N-Queens II | Hard | Array / General | O(n) | O(1) |
| 53 | Maximum Subarray | Medium | Tree & Graph | O(n) | O(n) |
| 54 | Spiral Matrix | Medium | Tree & Graph | O(n) | O(n) |
| 55 | Jump Game | Medium | Array / General | O(n) | O(1) |
| 56 | Merge Intervals | Medium | Heap | O(n) | O(n) |
| 57 | Insert Interval | Medium | Heap | O(n) | O(n) |
| 58 | Length of Last Word | Easy | Hash Map | O(n) | O(n) |
| 59 | Spiral Matrix II | Medium | Tree & Graph | O(n) | O(n) |
| 60 | Permutation Sequence | Hard | Backtracking | O(n) | O(1) |
| 62 | Unique Paths | Medium | Tree & Graph | O(n) | O(n) |
| 63 | Unique Paths II | Medium | Tree & Graph | O(n) | O(n) |
| 64 | Minimum Path Sum | Medium | Tree & Graph | O(n) | O(n) |
| 65 | Valid Number | Hard | Array / General | O(n) | O(1) |
| 66 | Plus One | Easy | Array / General | O(n) | O(1) |
| 67 | Add Binary | Easy | Tree & Graph | O(n) | O(n) |
| 68 | Text Justification | Hard | Heap | O(n) | O(n) |
| 69 | Sqrt(x) | Easy | Array / General | O(n) | O(1) |
| 70 | Climbing Stairs | Easy | Array / General | O(n) | O(1) |
| 71 | Simplify Path | Medium | Tree & Graph | O(n) | O(n) |
| 72 | Edit Distance | Medium | Array / General | O(n) | O(1) |
| 74 | Search a 2D Matrix | Medium | Tree & Graph | O(n) | O(n) |
| 85 | Maximal Rectangle | Hard | Math & Logic | O(n) | O(1) |
| 190 | Reverse Bits | Easy | Bit Manipulation | O(n) | O(1) |
| 301 | Remove Invalid Parentheses | Hard | Stack & Queue | O(n) | O(n) |
| 342 | Power of Four | Easy | Array / General | O(n) | O(1) |
| 344 | Reverse String | Easy | Array / General | O(n) | O(1) |
| 345 | Reverse Vowels of a String | Easy | Array / General | O(n) | O(1) |
| 349 | Intersection of Two Arrays | Easy | Two Pointers | O(n) | O(1) |
| 350 | Intersection of Two Arrays II | Easy | Two Pointers | O(n) | O(1) |
| 367 | Valid Perfect Square | Easy | Array / General | O(n) | O(1) |
| 374 | Guess Number Higher or Lower | Easy | Array / General | O(n) | O(1) |
| 383 | Ransom Note | Easy | Array / General | O(n) | O(1) |
| 387 | First Unique Character in a String | Easy | Array / General | O(n) | O(1) |
| 389 | Find the Difference | Easy | Array / General | O(n) | O(1) |
| 392 | Is Subsequence | Easy | Dynamic Programming | O(n) | O(n) |
| 401 | Binary Watch | Easy | Tree & Graph | O(n) | O(n) |
| 404 | Sum of Left Leaves | Easy | Tree & Graph | O(n) | O(n) |
| 405 | Convert a Number to Hexadecimal | Easy | Hash Map | O(n) | O(n) |
| 409 | Longest Palindrome | Easy | Two Pointers | O(n) | O(1) |
| 412 | Fizz Buzz | Easy | Array / General | O(n) | O(1) |
| 414 | Third Maximum Number | Easy | Array / General | O(n) | O(1) |
| 415 | Add Strings | Easy | Array / General | O(n) | O(1) |
| 434 | Number of Segments in a String | Easy | Array / General | O(n) | O(1) |
| 441 | Arranging Coins | Easy | Array / General | O(n) | O(1) |
| 455 | Assign Cookies | Easy | Array / General | O(n) | O(1) |
| 459 | Repeated Substring Pattern | Easy | Array / General | O(n) | O(1) |
| 461 | Hamming Distance | Easy | Bit Manipulation | O(n) | O(1) |
| 463 | Island Perimeter | Easy | Array / General | O(n) | O(1) |
| 476 | Number Complement | Easy | Hash Map | O(n) | O(n) |
| 482 | License Key Formatting | Easy | Array / General | O(n) | O(1) |
| 492 | Construct the Rectangle | Easy | Math & Logic | O(n) | O(1) |
| 495 | Teemo Attacking | Easy | Array / General | O(n) | O(1) |
| 496 | Next Greater Element I | Easy | Monotonic Stack | O(n) | O(n) |
| 500 | Keyboard Row | Easy | Array / General | O(n) | O(1) |
| 501 | Find Mode in Binary Search Tree | Easy | Binary Search | O(n) | O(1) |
| 504 | Base 7 | Easy | Hash Map | O(n) | O(n) |
| 506 | Relative Ranks | Easy | Array / General | O(n) | O(1) |
| 507 | Perfect Number | Easy | Array / General | O(n) | O(1) |
| 509 | Fibonacci Number | Easy | Array / General | O(n) | O(1) |
| 511 | Game Play Analysis I | Easy | Array / General | O(n) | O(1) |
| 520 | Detect Capital | Easy | Array / General | O(n) | O(1) |
| 521 | Longest Uncommon Subsequence I | Easy | Dynamic Programming | O(n) | O(n) |
| 530 | Minimum Absolute Difference in BST | Easy | Binary Search | O(n) | O(1) |
| 541 | Reverse String II | Easy | Array / General | O(n) | O(1) |
| 543 | Diameter of Binary Tree | Easy | Binary Search | O(n) | O(1) |
| 550 | Game Play Analysis IV | Medium | Tree & Graph | O(n) | O(n) |
| 551 | Student Attendance Record I | Easy | Monotonic Stack | O(n) | O(n) |
| 557 | Reverse Words in a String III | Easy | Array / General | O(n) | O(1) |
| 559 | Maximum Depth of N-ary Tree | Easy | Tree & Graph | O(n) | O(n) |
| 561 | Array Partition | Easy | Array / General | O(n) | O(1) |
| 563 | Binary Tree Tilt | Easy | Binary Search | O(n) | O(1) |
| 566 | Reshape the Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 570 | Managers with at Least 5 Direct Reports | Medium | Array / General | O(n) | O(1) |
| 572 | Subtree of Another Tree | Easy | Tree & Graph | O(n) | O(n) |
| 575 | Distribute Candies | Easy | Array / General | O(n) | O(1) |
| 589 | N-ary Tree Preorder Traversal | Easy | Tree & Graph | O(n) | O(n) |
| 590 | N-ary Tree Postorder Traversal | Easy | Tree & Graph | O(n) | O(n) |
| 594 | Longest Harmonious Subsequence | Easy | Dynamic Programming | O(n) | O(n) |
| 598 | Range Addition II | Easy | Array / General | O(n) | O(1) |
| 599 | Minimum Index Sum of Two Lists | Easy | Array / General | O(n) | O(1) |
| 605 | Can Place Flowers | Easy | Array / General | O(n) | O(1) |
| 617 | Merge Two Binary Trees | Easy | Tree & Graph | O(n) | O(n) |
| 637 | Average of Levels in Binary Tree | Easy | Binary Search | O(n) | O(1) |
| 643 | Maximum Average Subarray I | Easy | Array / General | O(n) | O(1) |
| 653 | Two Sum Iv Input Is A Bst | Medium | Binary Search | O(n) | O(1) |
| 657 | Robot Return to Origin | Easy | Array / General | O(n) | O(1) |
| 661 | Image Smoother | Easy | Array / General | O(n) | O(1) |
| 671 | Second Minimum Node In a Binary Tree | Easy | Two Pointers | O(n) | O(1) |
| 674 | Longest Continuous Increasing Subsequence | Easy | Dynamic Programming | O(n) | O(n) |
| 678 | Valid Parenthesis String | Medium | Array / General | O(n) | O(1) |
| 682 | Baseball Game | Easy | Bit Manipulation | O(n) | O(1) |
| 693 | Binary Number with Alternating Bits | Easy | Two Pointers | O(n) | O(1) |
| 696 | Count Binary Substrings | Easy | Tree & Graph | O(n) | O(n) |
| 697 | Degree of an Array | Easy | Hash Map | O(n) | O(n) |
| 700 | Search in a Binary Search Tree | Easy | Binary Search | O(n) | O(1) |
| 703 | Kth Largest Element in a Stream | Easy | Array / General | O(n) | O(1) |
| 704 | Binary Search | Easy | Binary Search | O(log n) | O(1) |
| 705 | Design HashSet | Easy | Hash Map | O(n) | O(n) |
| 706 | Design HashMap | Easy | Hash Map | O(n) | O(n) |
| 709 | To Lower Case | Easy | Array / General | O(n) | O(1) |
| 717 | 1-bit and 2-bit Characters | Easy | Bit Manipulation | O(n) | O(1) |
| 724 | Find Pivot Index | Easy | Array / General | O(n) | O(1) |
| 728 | Self Dividing Numbers | Easy | Array / General | O(n) | O(1) |
| 733 | Flood Fill | Easy | Array / General | O(n) | O(1) |
| 744 | Find Smallest Letter Greater Than Target | Easy | Prefix Sum | O(n) | O(n) |
| 746 | Min Cost Climbing Stairs | Easy | Array / General | O(n) | O(1) |
| 747 | Largest Number At Least Twice of Others | Easy | Array / General | O(n) | O(1) |
| 748 | Shortest Completing Word | Easy | Hash Map | O(n) | O(n) |
| 762 | Prime Number of Set Bits in Binary Representation | Easy | Two Pointers | O(n) | O(1) |
| 766 | Toeplitz Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 771 | Jewels and Stones | Easy | Array / General | O(n) | O(1) |
| 783 | Minimum Distance Between BST Nodes | Easy | Binary Search | O(n) | O(1) |
| 804 | Unique Morse Code Words | Easy | Array / General | O(n) | O(1) |
| 806 | Number of Lines To Write String | Easy | Array / General | O(n) | O(1) |
| 812 | Largest Triangle Area | Easy | Math & Logic | O(n) | O(1) |
| 819 | Most Common Word | Easy | Array / General | O(n) | O(1) |
| 821 | Shortest Distance to a Character | Easy | Array / General | O(n) | O(1) |
| 824 | Goat Latin | Easy | Array / General | O(n) | O(1) |
| 830 | Positions of Large Groups | Easy | Array / General | O(n) | O(1) |
| 832 | Flipping an Image | Easy | Array / General | O(n) | O(1) |
| 844 | Backspace String Compare | Easy | Array / General | O(n) | O(1) |
| 856 | Score of Parentheses | Medium | Stack & Queue | O(n) | O(n) |
| 859 | Buddy Strings | Easy | Array / General | O(n) | O(1) |
| 860 | Lemonade Change | Easy | Array / General | O(n) | O(1) |
| 867 | Transpose Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 868 | Binary Gap | Easy | Tree & Graph | O(n) | O(n) |
| 872 | Leaf-Similar Trees | Easy | Tree & Graph | O(n) | O(n) |
| 876 | Middle of the Linked List | Easy | Two Pointers | O(n) | O(1) |
| 883 | Projection Area of 3D Shapes | Easy | Array / General | O(n) | O(1) |
| 884 | Uncommon Words from Two Sentences | Easy | Array / General | O(n) | O(1) |
| 888 | Fair Candy Swap | Easy | Array / General | O(n) | O(1) |
| 892 | Surface Area of 3D Shapes | Easy | Array / General | O(n) | O(1) |
| 896 | Monotonic Array | Easy | Monotonic Stack | O(n) | O(n) |
| 897 | Increasing Order Search Tree | Easy | Binary Search | O(n) | O(1) |
| 905 | Sort Array By Parity | Easy | Hash Map | O(n) | O(n) |
| 908 | Smallest Range I | Easy | Array / General | O(n) | O(1) |
| 914 | X of a Kind in a Deck of Cards | Easy | Array / General | O(n) | O(1) |
| 917 | Reverse Only Letters | Easy | Array / General | O(n) | O(1) |
| 921 | Minimum Add to Make Parentheses Valid | Medium | Stack & Queue | O(n) | O(n) |
| 922 | Sort Array By Parity II | Easy | Array / General | O(n) | O(1) |
| 925 | Long Pressed Name | Easy | Array / General | O(n) | O(1) |
| 929 | Unique Email Addresses | Easy | Array / General | O(n) | O(1) |
| 933 | Number of Recent Calls | Easy | Array / General | O(n) | O(1) |
| 938 | Range Sum of BST | Easy | Binary Search | O(n) | O(1) |
| 941 | Valid Mountain Array | Easy | Array / General | O(n) | O(1) |
| 942 | DI String Match | Easy | Array / General | O(n) | O(1) |
| 944 | Delete Columns to Make Sorted | Easy | Array / General | O(n) | O(1) |
| 953 | Verifying an Alien Dictionary | Easy | Hash Map | O(n) | O(n) |
| 961 | N-Repeated Element in Size 2N Array | Easy | Array / General | O(n) | O(1) |
| 965 | Univalued Binary Tree | Easy | Binary Search | O(n) | O(1) |
| 976 | Largest Perimeter Triangle | Easy | Math & Logic | O(n) | O(1) |
| 977 | Squares of a Sorted Array | Easy | Array / General | O(n) | O(1) |
| 989 | Add to Array-Form of Integer | Easy | Array / General | O(n) | O(1) |
| 993 | Cousins in Binary Tree | Easy | Binary Search | O(n) | O(1) |
| 997 | Find the Town Judge | Easy | Array / General | O(n) | O(1) |
| 999 | Available Captures for Rook | Easy | Array / General | O(n) | O(1) |
| 1002 | Find Common Characters | Easy | Array / General | O(n) | O(1) |
| 1005 | Maximize Sum Of Array After K Negations | Easy | Array / General | O(n) | O(1) |
| 1009 | Complement of Base 10 Integer | Easy | Hash Map | O(n) | O(n) |
| 1018 | Binary Prefix Divisible By 5 | Easy | Prefix Sum | O(n) | O(n) |
| 1021 | Remove Outermost Parentheses | Easy | Stack & Queue | O(n) | O(n) |
| 1022 | Sum of Root To Leaf Binary Numbers | Easy | Tree & Graph | O(n) | O(n) |
| 1025 | Divisor Game | Easy | Array / General | O(n) | O(1) |
| 1030 | Matrix Cells in Distance Order | Easy | Tree & Graph | O(n) | O(n) |
| 1037 | Valid Boomerang | Easy | Array / General | O(n) | O(1) |
| 1046 | Last Stone Weight | Easy | Array / General | O(n) | O(1) |
| 1047 | Remove All Adjacent Duplicates In String | Easy | Array / General | O(n) | O(1) |
| 1051 | Height Checker | Easy | Array / General | O(n) | O(1) |
| 1071 | Greatest Common Divisor of Strings | Easy | Array / General | O(n) | O(1) |
| 1078 | Occurrences After Bigram | Easy | Array / General | O(n) | O(1) |
| 1089 | Duplicate Zeros | Easy | Array / General | O(n) | O(1) |
| 1103 | Distribute Candies to People | Easy | Array / General | O(n) | O(1) |
| 1108 | Defanging an IP Address | Easy | Array / General | O(n) | O(1) |
| 1122 | Relative Sort Array | Easy | Hash Map | O(n) | O(n) |
| 1128 | Number of Equivalent Domino Pairs | Easy | Array / General | O(n) | O(1) |
| 1137 | N-th Tribonacci Number | Easy | Bit Manipulation | O(n) | O(1) |
| 1154 | Day of the Year | Easy | Array / General | O(n) | O(1) |
| 1160 | Find Words That Can Be Formed by Characters | Easy | Tree & Graph | O(n) | O(n) |
| 1175 | Prime Arrangements | Easy | Bit Manipulation | O(n) | O(1) |
| 1185 | Day of the Week | Easy | Array / General | O(n) | O(1) |
| 1200 | Minimum Absolute Difference | Easy | Array / General | O(n) | O(1) |
| 1207 | Unique Number of Occurrences | Easy | Array / General | O(n) | O(1) |
| 1217 | Minimum Cost to Move Chips to The Same Position | Easy | Array / General | O(n) | O(1) |
| 1221 | Split a String in Balanced Strings | Easy | Array / General | O(n) | O(1) |
| 1232 | Check If It Is a Straight Line | Easy | Array / General | O(n) | O(1) |
| 1252 | Cells with Odd Values in a Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 1266 | Minimum Time Visiting All Points | Easy | Array / General | O(n) | O(1) |
| 1275 | Find Winner on a Tic Tac Toe Game | Easy | Array / General | O(n) | O(1) |
| 1281 | Subtract the Product and Sum of Digits of an Integer | Easy | Math & Logic | O(n) | O(1) |
| 1287 | Element Appearing More Than 25% In Sorted Array | Easy | Array / General | O(n) | O(1) |
| 1290 | Convert Binary Number in a Linked List to Integer | Easy | Binary Search | O(n) | O(1) |
| 1295 | Find Numbers with Even Number of Digits | Easy | Math & Logic | O(n) | O(1) |
| 1299 | Replace Elements with Greatest Element on Right Side | Easy | Array / General | O(n) | O(1) |
| 1309 | Decrypt String from Alphabet to Integer Mapping | Easy | Array / General | O(n) | O(1) |
| 1313 | Decompress Run-Length Encoded List | Easy | Array / General | O(n) | O(1) |
| 1317 | Convert Integer to the Sum of Two No-Zero Integers | Easy | Array / General | O(n) | O(1) |
| 1323 | Maximum 69 Number | Easy | Array / General | O(n) | O(1) |
| 1332 | Remove Palindromic Subsequences | Easy | Dynamic Programming | O(n) | O(n) |
| 1337 | The K Weakest Rows in a Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 1342 | Number of Steps to Reduce a Number to Zero | Easy | Array / General | O(n) | O(1) |
| 1346 | Check If N and Its Double Exist | Easy | Array / General | O(n) | O(1) |
| 1351 | Count Negative Numbers in a Sorted Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 1356 | Sort Integers by The Number of 1 Bits | Easy | Bit Manipulation | O(n) | O(1) |
| 1360 | Number of Days Between Two Dates | Easy | Array / General | O(n) | O(1) |
| 1370 | Increasing Decreasing String | Easy | Array / General | O(n) | O(1) |
| 1374 | Generate a String With Characters That Have Odd Counts | Easy | Array / General | O(n) | O(1) |
| 1379 | Find a Corresponding Node of a Binary Tree in a Clone of That Tree | Easy | Binary Search | O(n) | O(1) |
| 1380 | Lucky Numbers in a Matrix | Easy | Tree & Graph | O(n) | O(n) |
| 1385 | Find the Distance Value Between Two Arrays | Easy | Array / General | O(n) | O(1) |
| 1389 | Create Target Array in the Given Order | Easy | Array / General | O(n) | O(1) |
| 1394 | Find Lucky Integer in an Array | Easy | Hash Map | O(n) | O(n) |
| 1399 | Count Largest Group | Easy | Array / General | O(n) | O(1) |
| 1403 | Minimum Subsequence in Non-Increasing Order | Easy | Dynamic Programming | O(n) | O(n) |
| 1408 | String Matching in an Array | Easy | Array / General | O(n) | O(1) |
| 1413 | Minimum Value to Get Positive Step by Step Sum | Easy | Array / General | O(n) | O(1) |
| 1417 | Reformat The String | Easy | Array / General | O(n) | O(1) |
| 1422 | Maximum Score After Splitting a String | Easy | Array / General | O(n) | O(1) |
| 1431 | Kids With the Greatest Number of Candies | Easy | Array / General | O(n) | O(1) |
| 1436 | Destination City | Easy | Array / General | O(n) | O(1) |
| 1437 | Check If All 1's Are at Least Length K Places Away | Easy | Array / General | O(n) | O(1) |
| 1446 | Consecutive Characters | Easy | Array / General | O(n) | O(1) |
| 1450 | Number of Students Doing Homework at a Given Time | Easy | Array / General | O(n) | O(1) |
| 1455 | Check If a Word Occurs As a Prefix of Any Word in a Sentence | Easy | Prefix Sum | O(n) | O(n) |
| 1460 | Make Two Arrays Equal by Reversing Subarrays | Easy | Array / General | O(n) | O(1) |
| 1480 | Running Sum of 1d Array | Easy | Array / General | O(n) | O(1) |
| 1486 | XOR Operation in an Array | Easy | Bit Manipulation | O(n) | O(1) |
| 1491 | Average Salary Excluding the Minimum and Maximum Salary | Easy | Array / General | O(n) | O(1) |
| 1496 | Path Crossing | Easy | Tree & Graph | O(n) | O(n) |
| 1502 | Can Make Arithmetic Progression From Sequence | Easy | Array / General | O(n) | O(1) |
| 1507 | Reformat Date | Easy | Array / General | O(n) | O(1) |
| 1512 | Number of Good Pairs | Easy | Array / General | O(n) | O(1) |
| 1518 | Water Bottles | Easy | Array / General | O(n) | O(1) |
| 1523 | Count Odd Numbers in an Interval Range | Easy | Heap | O(n) | O(n) |
| 1528 | Shuffle String | Easy | Array / General | O(n) | O(1) |
| 1541 | Minimum Insertions to Balance a Parentheses String | Medium | Stack & Queue | O(n) | O(n) |
| 1544 | Make The String Great | Easy | Array / General | O(n) | O(1) |
| 1550 | Three Consecutive Odds | Easy | Array / General | O(n) | O(1) |
| 1556 | Thousand Separator | Easy | Array / General | O(n) | O(1) |
| 1566 | Detect Pattern of Length M Repeated K or More Times | Easy | Hash Map | O(n) | O(n) |
| 1572 | Matrix Diagonal Sum | Easy | Tree & Graph | O(n) | O(n) |
| 1682 | Most Visited Sector In A Circular Track | Medium | Array / General | O(n) | O(1) |
| 1840 | Maximum Building Height | Hard | Tree & Graph | O(n) | O(n) |
| 2877 | Create a DataFrame from List | Easy | Two Pointers | O(n) | O(1) |
| 2878 | Get the Size of a DataFrame | Easy | Two Pointers | O(n) | O(1) |
| 2879 | Display the First Three Rows | Easy | Array / General | O(n) | O(1) |
| 2880 | Select Data | Easy | Bit Manipulation | O(n) | O(1) |
| 2881 | Create a New Column | Easy | Two Pointers | O(n) | O(1) |
| 2882 | Drop Duplicate Rows | Easy | Array / General | O(n) | O(1) |
| 2883 | Drop Missing Data | Easy | Bit Manipulation | O(n) | O(1) |
| 2884 | Modify Columns | Easy | Tree & Graph | O(n) | O(n) |
| 2885 | Rename Columns | Easy | Tree & Graph | O(n) | O(n) |
| 2886 | Change Data Type | Easy | Bit Manipulation | O(n) | O(1) |
| 2887 | Fill Missing Data | Easy | Bit Manipulation | O(n) | O(1) |
| 2888 | Reshape Data: Concatenate | Easy | Stack & Queue | O(n) | O(n) |
| 2889 | Reshape Data: Pivot | Easy | Tree & Graph | O(n) | O(n) |
| 2890 | Reshape Data: Melt | Easy | Bit Manipulation | O(n) | O(1) |
| 2891 | Method Chaining | Easy | Hash Map | O(n) | O(n) |
| 3093 | Longest Common Suffix Queries | Hard | Hash Map | O(n) | O(n) |
| 3161 | Block Placement Queries | Hard | Array / General | O(n) | O(1) |
| 3348 | Smallest Divisible Digit Product II | Hard | Math & Logic | O(n) | O(1) |
| 3475 | DNA Pattern Recognition | Medium | Array / General | O(n) | O(1) |
| 3482 | Analyze Organization Hierarchy | Hard | Array / General | O(n) | O(1) |
| 3497 | Analyze Subscription Conversion | Medium | Array / General | O(n) | O(1) |
| 3498 | Reverse Degree of a String | Easy | Array / General | O(n) | O(1) |
| 3521 | Find Product Recommendation Pairs | Medium | Array / General | O(n) | O(1) |
| 3554 | Find Category Recommendation Pairs | Hard | Array / General | O(n) | O(1) |
| 3559 | Number of Ways to Assign Edge Weights II | Hard | Tree & Graph | O(n) | O(n) |
| 3564 | Seasonal Sales Analysis | Medium | Array / General | O(n) | O(1) |
| 3570 | Find Books with No Available Copies | Easy | Array / General | O(n) | O(1) |
| 3580 | Find Consistently Improving Employees | Medium | Array / General | O(n) | O(1) |
| 3586 | Find COVID Recovery Patients | Medium | Array / General | O(n) | O(1) |
| 3601 | Find Drivers with Improved Fuel Efficiency | Medium | Array / General | O(n) | O(1) |
| 3611 | Find Overbooked Employees | Medium | Array / General | O(n) | O(1) |
| 3614 | Process String with Special Operations II | Hard | Tree & Graph | O(n) | O(n) |
| 3691 | Maximum Total Subarray Value II | Hard | Array / General | O(n) | O(1) |
| 3705 | Find Golden Hour Customers | Medium | Array / General | O(n) | O(1) |
| 3716 | Find Churn Risk Customers | Medium | Array / General | O(n) | O(1) |
| 3753 | Total Waviness of Numbers in Range II | Hard | Array / General | O(n) | O(1) |