- 1. Backtracking
- 2. Base Conversion
- 3. Bellman Ford
- 4. BFS
- 5. Binary Search
- 6. Binary Trees
- 7. Bit Manipulation
- 8. Bitmasks
- 9. Count Pairs In Array
- 10. Custom Comparator
- 11. Design and Implementation
- 12. DFS
- 13. Dijkstra
- 14. Dynamic Programming
- 15. Euler Circuit
- 16. Fenwick Tree
- 17. Greedy Scheduling
- 18. Heaps (Priority Queues)
- 19. Intervals
- 20. Line Sweep
- 21. Linked List
- 22. LIS
- 23. Manacher
- 24. Matrix
- 25. Merge Sort
- 26. Minimum Spanning Trees
- 27. Prefix State Map
- 28. Queries
- 29. Rolling Hash
- 30. Segment Tree
- 31. Sets
- 32. Sieve of Eratosthenes
- 33. Sliding Window
- 34. Stack
- 35. Stringstream
- 36. Sum of First N Natural Numbers
- 37. Topological Sort
- 38. Trie
- 39. Two Dimensional Plane
- 40. Two Pointer
- 41. Union Find
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Generate Parentheses | Medium | Solution |
| 2 | Combination Sum | Medium | Solution |
| 3 | Permutations | Medium | Solution |
| 4 | Letter Combinations of a Phone Number | Medium | Solution |
| 5 | Generate Parentheses | Medium | Solution |
| 6 | Sudoku Solver | Medium | Solution |
| 7 | Combination Sum II | Medium | Solution |
| 8 | Permutations II | Medium | Solution |
| 9 | N Queens | Medium | Solution |
| 10 | Combinations | Medium | Solution |
| 11 | Subsets | Medium | Solution |
| 12 | Word Search | Medium | Solution |
| 13 | Subsets II | Medium | Solution |
| 14 | Palindrome Partitioning | Medium | Solution |
| 15 | Combination Sum III | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find Unique Binary String | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Cheapest Flights Within K Stops | Medium | Solution |
| 2 | Network Delay Time | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Average of Levels In Binary Tree | Easy | Solution |
| 2 | Number of Islands | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Search In Rotated Sorted Array | Medium | Solution |
| 2 | Find First and Last Position of Element In Sorted Array | Medium | Solution |
| 3 | Minimize Maximum of Array | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sum of Leaft Leaves | Easy | Solution |
| 2 | Construct String From Binary Tree | Easy | Solution |
| 3 | Average of Levels In Binary Tree | Easy | Solution |
| 4 | Balanced Binary Tree | Easy | Solution |
| 5 | Convert Sorted Array To Binary Search Tree | Easy | Solution |
| 6 | Sum Root To Leaf Numbers | Medium | Solution |
| 7 | Kth Smallest Element in a BST | Medium | Solution |
| 8 | Lowest Common Ancestor Of A Binary Tree | Medium | Solution |
| 9 | Serialize and Deserialize BST | Medium | Solution |
| 10 | Construct Binary Tree From Inorder and Postorder Traversal | Medium | Solution |
| 11 | Construct Binary Tree From Preorder and Inorder Traversal | Medium | Solution |
| 12 | Binary Tree Pruning | Medium | Solution |
| 13 | All Nodes Distance K In Binary Tree | Medium | Solution |
| 14 | Distribute Coins In Binary Tree | Medium | Solution |
| 15 | Vertical Order Traversal of A Binary Tree | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Power of Two | Easy | Solution |
| 2 | Divide Array Into Equal Pairs | Easy | Solution |
| 3 | Divide Two Integers | Medium | Solution |
| 4 | Subsets | Medium | Solution |
| 5 | Subsets II | Medium | Solution |
| 6 | Check If A String Contains All Binary Codes of Size K | Medium | Solution |
| 7 | Concatenation of Consecutive Binary Numbers | Medium | Solution |
| 8 | Count Number of Maximum Bitwise OR Subsets | Medium | Solution |
| 9 | Largest Combination With Bitwise AND Greater Than Zero | Medium | Solution |
| 10 | Maximum XOR After Operations | Medium | Solution |
| 11 | Smallest Subarrays With Maximum Bitwise OR | Medium | Solution |
| 12 | Longest Subarray With Maximum Bitwise AND | Medium | Solution |
| 13 | Minimize XOR | Medium | Solution |
| 14 | Bitwise XOR of All Pairings | Medium | Solution |
| 15 | Closest Subsequence Sum | Hard | Solution |
| 16 | Find The Shortest Superstring | Hard | Solution |
| 17 | Number of One Bits | Easy | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Fair Distribution of Cookies | Medium | Solution |
| 2 | Count Number of Maximum Bitwise OR Subsets | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Nice Pairs In An Array | Medium | Solution |
| 2 | Count Number of Bad Pairs | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sort The People | Medium | Solution |
| 2 | Sort Array By Parity | Medium | Solution |
| 3 | Bitwise XOR of All Pairings | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Implement Queue Using Stacks | Easy | Solution |
| 2 | Implement Stack Using Queues | Easy | Solution |
| 3 | Stock Price Fluctuation | Medium | Solution |
| 4 | Design Circular Deque | Medium | Solution |
| 5 | LRU Cache | Medium | Solution |
| 6 | Time Based Key Value Store | Medium | Solution |
| 7 | Operations On Tree | Medium | Solution |
| 8 | Design Circular Queue | Medium | Solution |
| 9 | Design Movie Rental System | Hard | Solution |
| 10 | Design A Text Editor | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Flood Fill | Easy | Solution |
| 2 | Is Graph Bipartite? | Medium | Solution |
| 3 | Keys and Rooms | Medium | Solution |
| 4 | Out of Boundary Paths | Medium | Solution |
| 5 | Number of Provinces | Medium | Solution |
| 6 | Pacific Atlantic Water Flow | Medium | Solution |
| 7 | Interleaving String | Medium | Solution |
| 8 | Shortest Bridge | Medium | Solution |
| 9 | Throne Inheritance | Medium | Solution |
| 10 | Detonate The Maximum Bombs | Medium | Solution |
| 11 | Longest Path With Different Adjacent Characters | Hard | Solution |
| 12 | Create Components With Same Value | Hard | Solution |
| 13 | Restore the Array From Adjacent Pairs | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Network Delay Time | Medium | Solution |
| 2 | Cheapest Flights Within K Stops | Medium | Solution |
| 3 | Path With Maximum Probability | Medium | Solution |
| 4 | Find The City With The Smallest Number of Neighbors At A Threshold Distance | Medium | Solution |
| 5 | Path With Minimum Effort | Medium | Solution |
| 6 | Number of Restricted Paths From First To Last Node | Medium | Solution |
| 7 | Number of Ways To Arrive At Destination | Medium | Solution |
| 8 | Minimum Cost To Reach Destination In Time | Medium | Solution |
| 9 | Minimum Cost To Make At Least One Valid Path In A Grid | Hard | Solution |
| 10 | Reachable Nodes in Subdivided Graph | Hard | Solution |
| 11 | Design Graph With Shortest Path Calculator | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Climbing Stairs | Easy | Solution |
| 2 | Pascal's Triangle | Easy | Solution |
| 3 | Best Time To Buy and Sell Stock | Easy | Solution |
| 4 | Jump Game | Medium | Solution |
| 5 | Unique Paths | Medium | Solution |
| 6 | Decode Ways | Medium | Solution |
| 7 | Maximum Product Subarray | Medium | Solution |
| 8 | House Robber | Medium | Solution |
| 9 | Word Break | Medium | Solution |
| 10 | Coin Change | Medium | Solution |
| 11 | Count Number of Texts | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Reconstruct Itinerary | Hard | Solution |
| 2 | Cracking The Safe | Hard | Solution |
| 3 | Valid Arrangement of Pairs | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Shifting Letters II | Medium | Solution |
| 2 | Queries On A Permutation With Key | Medium | Solution |
| 3 | Create Sorted Array Through Instructions | Hard | Solution |
| 4 | Count Good Triplets In An Array | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Maximum Number of Events That Can Be Attended | Medium | Solution |
| 2 | Single Threaded CPU | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sort Array By Increasing Frequency | Easy | Solution |
| 2 | Kth Largest Element in An Array | Medium | Solution |
| 3 | Top K Frequent Elements | Medium | Solution |
| 4 | Sort Characters By Frequency | Medium | Solution |
| 5 | Find K Closest Elements | Medium | Solution |
| 6 | Top K Frequent Words | Medium | Solution |
| 7 | K Closest Points To Origin | Medium | Solution |
| 8 | Reduce Array Size To The Half | Medium | Solution |
| 9 | Reorganize String | Medium | Solution |
| 10 | Sender With Largest Word Count | Medium | Solution |
| 11 | Minimum Difference In Sums After Removal of Elements | Hard | Solution |
| 12 | Course Schedule III | Hard | Solution |
| 13 | Maximum Frequency Stack | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Merge Intervals | Medium | Solution |
| 2 | Insert Interval | Medium | Solution |
| 3 | Non Overlapping Intervals | Medium | Solution |
| 4 | Minimum Number of Arrows To Burst Balloons | Medium | Solution |
| 5 | My Calendar I | Medium | Solution |
| 6 | Video Stitching | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Maximum Population Year | Easy | Solution |
| 2 | Divide Intervals Into Minimum Number of Groups | Medium | Solution |
| 3 | Shifting Letters II | Medium | Solution |
| 4 | Describe The Painting | Medium | Solution |
| 5 | Minimum Absolute Difference Queries | Medium | Solution |
| 6 | Car Pooling | Medium | Solution |
| 7 | Corporate Flight Bookings | Medium | Solution |
| 8 | My Calendar II | Medium | Solution |
| 9 | Minimum Interval To Include Each Query | Hard | Solution |
| 10 | My Calendar III | Hard | Solution |
| 11 | The Skyline Problem | Hard | Solution |
| 12 | Number of Flowers In Full Bloom | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Longest Increasing Subsequence | Medium | Solution |
| 2 | Increasing Triplet Subsequence | Medium | Solution |
| 3 | Minimum Number of Removals To Make Mountain Array | Hard | Solution |
| 4 | Find The Longest Valid Obstacle Course At Each Position | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Longest Palindromic Substring | Medium | Solution |
| 2 | Maximum Product of The Length of Two Palindromic Substrings | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Transpost Matrix | Easy | Solution |
| 2 | Count Submatrices With All Ones | Medium | Solution |
| 3 | Maximal Square | Medium | Solution |
| 4 | Shortest Path In Binary Matrix | Medium | Solution |
| 5 | Sort The Matrix Diagonally | Medium | Solution |
| 6 | Count Square Submatrices With All Ones | Medium | Solution |
| 7 | Number of Submatrices That Sum To Target | Hard | Solution |
| 8 | Maximal Rectangle | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sort List | Medium | Solution |
| 2 | Count of Smaller Numbers After Self | Medium | Solution |
| 3 | Count of Range Sum | Medium | Solution |
| 4 | Reverse Pairs | Medium | Solution |
| 5 | Number of Pairs Satisfying Inequality | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Min Cost To Connect All Points | Medium | Solution |
| 2 | Find Critical And Pseudo Critical Edges in Minimum Spanning Tree | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Contiguous Array | Medium | Solution |
| 2 | Find The Longest Substring Containing Vowels In Even Counts | Medium | Solution |
| 3 | Find Longest Awesome Substring | Medium | Solution |
| 4 | Number of Wonderful Substrings | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Most Beautiful Item For Each Query | Medium | Solution |
| 2 | Queries On Number of Points Inside A Circle | Medium | Solution |
| 3 | Range Frequency Queries | Medium | Solution |
| 4 | XOR Queries of a Subarray | Medium | Solution |
| 5 | Queries On A Permutation With Key | Medium | Solution |
| 6 | Subrectangle Queries | Medium | Solution |
| 7 | Minimum Absolute Difference Queries | Medium | Solution |
| 8 | Maximum Genetic Difference Query | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Repeated DNA Sequences | Medium | Solution |
| 2 | Shortest Palindrome | Medium | Solution |
| 3 | Longest Duplicate Substring | Medium | Solution |
| 4 | Distinct Echo Substrings | Medium | Solution |
| 5 | K Divisible Elements Subarrays | Medium | Solution |
| 6 | Sum of Scores of Built Strings | Hard | Solution |
| 7 | Find Substring With Given Hash Value | Hard | Solution |
| 8 | Longest Common Subpath | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sum of Even Numbers After Queries | Medium | Solution |
| 2 | Range Sum Query - Mutable | Medium | Solution |
| 3 | Longest Increasing Subseqence - II | Medium | Solution |
| 4 | Shifting Letters - II | Medium | Solution |
| 5 | Falling Squares | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find All Numbers Disappeared in an Array | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Primes | Medium | Solution |
| 2 | Four Divisors | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Longest Substring Without Repeating Characters | Medium | Solution |
| 2 | Minimum Size Subarray Sum | Medium | Solution |
| 3 | Number of Smooth Descent Periods of Stock | Medium | Solution |
| 4 | Maximize The Confusion of An Exam | Medium | Solution |
| 5 | Frequency of Most Frequent Element | Medium | Solution |
| 6 | Max Consecutive Ones - III | Medium | Solution |
| 7 | Longest Repeating Character Replacement | Medium | Solution |
| 8 | Permutation In String | Medium | Solution |
| 9 | Minimum Window Substring | Hard | Solution |
| 10 | Substring With Concatenation Of All Words | Hard | Solution |
| 11 | Count Subarrays With Fixed Count | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Valid Parentheses | Easy | Solution |
| 2 | Implement Queue Using Stacks | Easy | Solution |
| 3 | Next Greater Element I | Easy | Solution |
| 4 | Backspace String Compare | Easy | Solution |
| 5 | Min Stack | Medium | Solution |
| 6 | Next Greater Element II | Medium | Solution |
| 7 | 132 Patterns | Medium | Solution |
| 8 | Daily Temperatures | Medium | Solution |
| 9 | Score of Parentheses | Medium | Solution |
| 10 | Validate Stack Sequences | Medium | Solution |
| 11 | Next Greater Node In Linked List | Medium | Solution |
| 12 | The Number of Weak Characters In The Game | Medium | Solution |
| 13 | Construct Smallest Number From DI String | Medium | Solution |
| 14 | Maximum Frequency Stack | Medium | Solution |
| 15 | Basic Calculator | Medium | Solution |
| 16 | Longest Valid Parentheses | Medium | Solution |
| 17 | Using A Robot To Print The Lexicographically Smallest String | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Reverse Words In A String-III | Medium | Solution |
| 2 | Find Duplicate File In System | Medium | Solution |
| 3 | Apply Discount To Prices | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Number of Homogenous Substrings | Medium | Solution |
| 2 | Number of Substrings With Only 1s | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Course Schedule | Medium | Solution |
| 2 | Course Schedule II | Medium | Solution |
| 3 | Minimum Height Trees | Medium | Solution |
| 4 | Longest Incresing Path In A Matrix | Medium | Solution |
| 5 | All Ancestors of a Node In Directed Acyclic Graph | Medium | Solution |
| 6 | Number of Ways To Arrive At Destination | Medium | Solution |
| 7 | Parallel Courses III | Hard | Solution |
| 8 | Build A Matrix With Conditions | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Implement Trie (Prefix Tree) | Medium | Solution |
| 2 | Search Suggestions System | Medium | Solution |
| 3 | Maximum XOR of Two Numbers In An Array | Medium | Solution |
| 4 | K Divisible Elements Subarray | Medium | Solution |
| 5 | Maximum Genetic Difference Query | Hard | Solution |
| 6 | Concatenated Words | Hard | Solution |
| 7 | Palindrome Pairs | Hard | Solution |
| 8 | Sum of Prefix Scores of Strings | Hard | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Max Points On A Line | Medium | Solution |
| 2 | Min Cost To Connect All Points | Medium | Solution |
| 3 | Queries On Number of Points Inside A Circle | Medium | Solution |
| 4 | Detonate The Maximum Bombs | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Two Sum | Easy | Solution |
| 2 | Remove Duplicates From Sorted List | Easy | Solution |
| 3 | Linked List Cycle | Easy | Solution |
| 4 | Add Two Numbers | Medium | Solution |
| 5 | Container With Most Water | Medium | Solution |
| 6 | 3Sum | Medium | Solution |
| 7 | 3Sum Closest | Medium | Solution |
| 8 | Remove Nth Node From End of List | Medium | Solution |
| 9 | Trapping Rain Water | Medium | Solution |
| 10 | Sort Colors | Medium | Solution |
| 11 | Minimum Window Substring | Medium | Solution |
| 12 | Linked List Cycle-II | Medium | Solution |
| 13 | Reorder List | Medium | Solution |
| 14 | Sort List | Medium | Solution |
| 15 | Maximum Product Subarray | Medium | Solution |
| 16 | Lexicographically Smallest Palindrome | Medium | Solution |
| S.No | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Longest Consecutive Sequence | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| 3 | Number of Provinces | Medium | Solution |
| 4 | Redundant Connections | Medium | Solution |
| 5 | Max Area of Island | Medium | Solution |
| 6 | Is Graph Bipartite ? | Medium | Solution |
| 7 | Satifiability of Equality Equations | Medium | Solution |
| 8 | Smallest String With Swaps | Medium | Solution |
| 9 | Number of Good Paths | Medium | Solution |