Practice
Every problem from the DSA sheet, grouped by topic. Hit Solve to open the workspace with the description, editorial, sample tests, and an embedded C++, Python, and Java editor.
Arrays
65| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Best Time to Buy and Sell Stock | Easy | Arrays | Solve |
| Can Place Flowers | Easy | Arrays | Solve |
| Concatenation of Array | Easy | Arrays | Solve |
| Contains Duplicate | Easy | Arrays | Solve |
| Design HashMap | Easy | Arrays | Solve |
| Design HashSet | Easy | Arrays | Solve |
| Design Parking System | Easy | Arrays | Solve |
| Find All Numbers Disappeared in An Array | Easy | Arrays | Solve |
| Find Pivot Index | Easy | Arrays | Solve |
| Find the Difference of Two Arrays | Easy | Arrays | Solve |
| Find The Index of The First Occurrence in a String | Easy | Arrays | Solve |
| Is Subsequence | Easy | Arrays | Solve |
| Isomorphic Strings | Easy | Arrays | Solve |
| Length of Last Word | Easy | Arrays | Solve |
| Majority Element | Easy | Arrays | Solve |
| Maximum Number of Balloons | Easy | Arrays | Solve |
| Maximum Subarray | Easy | Arrays | Solve |
| Move Zeroes | Easy | Arrays | Solve |
| Pascal's Triangle | Easy | Arrays | Solve |
| Pascals Triangle | Easy | Arrays | Solve |
| Range Sum Query - Immutable | Easy | Arrays | Solve |
| Remove Element | Easy | Arrays | Solve |
| Replace Elements With Greatest Element On Right Side | Easy | Arrays | Solve |
| Sign of An Array | Easy | Arrays | Solve |
| Two Sum | Easy | Arrays | Solve |
| Unique Email Addresses | Easy | Arrays | Solve |
| Word Pattern | Easy | Arrays | Solve |
| Best Time to Buy And Sell Stock II | Medium | Arrays | Solve |
| Brick Wall | Medium | Arrays | Solve |
| Check if a String Contains all Binary Codes of Size K | Medium | Arrays | Solve |
| Continuous Subarray Sum | Medium | Arrays | Solve |
| Design Underground System | Medium | Arrays | Solve |
| Encode and Decode TinyURL | Medium | Arrays | Solve |
| Find All Anagrams in a String | Medium | Arrays | Solve |
| Find Duplicate Number | Medium | Arrays | Solve |
| Grid Game | Medium | Arrays | Solve |
| Insert Delete Get Random O(1) | Medium | Arrays | Solve |
| Insert Interval | Medium | Arrays | Solve |
| Longest Consecutive Sequence | Medium | Arrays | Solve |
| Majority Element II | Medium | Arrays | Solve |
| Maximum Product of The Length of Two Palindromic Subsequences | Medium | Arrays | Solve |
| Maximum Product Subarray | Medium | Arrays | Solve |
| Merge Intervals | Medium | Arrays | Solve |
| Minimum Number of Swaps to Make The String Balanced | Medium | Arrays | Solve |
| Minimum Penalty for a Shop | Medium | Arrays | Solve |
| Next Permutation | Medium | Arrays | Solve |
| Non Decreasing Array | Medium | Arrays | Solve |
| Number of Pairs of Interchangeable Rectangles | Medium | Arrays | Solve |
| Number of Zero-Filled Subarrays | Medium | Arrays | Solve |
| Optimal Partition of String | Medium | Arrays | Solve |
| Product of Array Except Self | Medium | Arrays | Solve |
| Push Dominoes | Medium | Arrays | Solve |
| Range Sum Query 2D Immutable | Medium | Arrays | Solve |
| Repeated DNA Sequences | Medium | Arrays | Solve |
| Rotate Array | Medium | Arrays | Solve |
| Sort an Array | Medium | Arrays | Solve |
| Sort Colors | Medium | Arrays | Solve |
| Subarray Sum Equals K | Medium | Arrays | Solve |
| Top K Frequent Elements | Medium | Arrays | Solve |
| Unique Length 3 Palindromic Subsequences | Medium | Arrays | Solve |
| Valid Sudoku | Medium | Arrays | Solve |
| Wiggle Sort | Medium | Arrays | Solve |
| First Missing Positive | Hard | Arrays | Solve |
| Naming a Company | Hard | Arrays | Solve |
| Text Justification | Hard | Arrays | Solve |
Strings
12| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Valid Anagram | Easy | Strings | Solve |
| Valid Palindrome | Easy | Strings | Solve |
| Count and Say | Medium | Strings | Solve |
| Encode and Decode Strings | Medium | Strings | Solve |
| Group Anagrams | Medium | Strings | Solve |
| KMP Algorithm / Find the Index of the First Occurrence in a String | Medium | Strings | Solve |
| Longest Palindromic Substring | Medium | Strings | Solve |
| Palindromic Substrings | Medium | Strings | Solve |
| Rabin-Karp / Repeated String Match | Medium | Strings | Solve |
| Reverse Words in a String | Medium | Strings | Solve |
| String to Integer (atoi) | Medium | Strings | Solve |
| Zigzag Conversion | Medium | Strings | Solve |
Two Pointers
18| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Merge Sorted Array | Easy | Two Pointers | Solve |
| Merge Strings Alternately | Easy | Two Pointers | Solve |
| Minimum Difference Between Highest And Lowest of K Scores | Easy | Two Pointers | Solve |
| Remove Duplicates From Sorted Array | Easy | Two Pointers | Solve |
| Reverse String | Easy | Two Pointers | Solve |
| Valid Palindrome II | Easy | Two Pointers | Solve |
| 3Sum | Medium | Two Pointers | Solve |
| 3Sum Closest | Medium | Two Pointers | Solve |
| 4Sum | Medium | Two Pointers | Solve |
| Array With Elements Not Equal to Average of Neighbors | Medium | Two Pointers | Solve |
| Boats to Save People | Medium | Two Pointers | Solve |
| Container With Most Water | Medium | Two Pointers | Solve |
| Count the Number of Good Subarrays | Medium | Two Pointers | Solve |
| Minimum Operations to Reduce X to Zero | Medium | Two Pointers | Solve |
| Number of Subsequences That Satisfy The Given Sum Condition | Medium | Two Pointers | Solve |
| Remove Duplicates from Sorted Array II | Medium | Two Pointers | Solve |
| Two Sum II Input Array Is Sorted | Medium | Two Pointers | Solve |
| Trapping Rain Water | Hard | Two Pointers | Solve |
Sliding Window
18| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Contains Duplicate II | Easy | Sliding Window | Solve |
| Count Number of Nice Subarrays | Medium | Sliding Window | Solve |
| Find K Closest Elements | Medium | Sliding Window | Solve |
| Frequency of The Most Frequent Element | Medium | Sliding Window | Solve |
| Fruit Into Baskets | Medium | Sliding Window | Solve |
| Fruits into Basket | Medium | Sliding Window | Solve |
| Longest Repeating Character Replacement | Medium | Sliding Window | Solve |
| Longest Substring Without Repeating Characters | Medium | Sliding Window | Solve |
| Max Consecutive Ones III | Medium | Sliding Window | Solve |
| Maximum Number of Vowels in a Substring of Given Length | Medium | Sliding Window | Solve |
| Maximum Points You Can Obtain from Cards | Medium | Sliding Window | Solve |
| Minimum Number of Flips to Make The Binary String Alternating | Medium | Sliding Window | Solve |
| Minimum Size Subarray Sum | Medium | Sliding Window | Solve |
| Number of Sub Arrays of Size K and Avg Greater than or Equal to Threshold | Medium | Sliding Window | Solve |
| Permutation in String | Medium | Sliding Window | Solve |
| Subarray Product Less Than K | Medium | Sliding Window | Solve |
| Minimum Window Substring | Hard | Sliding Window | Solve |
| Sliding Window Maximum | Hard | Sliding Window | Solve |
Binary Search
24| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Arranging Coins | Easy | Binary Search | Solve |
| Binary Search | Easy | Binary Search | Solve |
| Guess Number Higher Or Lower | Easy | Binary Search | Solve |
| Search Insert Position | Easy | Binary Search | Solve |
| Squares of a Sorted Array | Easy | Binary Search | Solve |
| Valid Perfect Square | Easy | Binary Search | Solve |
| Aggressive Cows | Medium | Binary Search | Solve |
| Capacity to Ship Packages | Medium | Binary Search | Solve |
| Find First And Last Position of Element In Sorted Array | Medium | Binary Search | Solve |
| Find Minimum in Rotated Sorted Array | Medium | Binary Search | Solve |
| Find Peak Element | Medium | Binary Search | Solve |
| Koko Eating Bananas | Medium | Binary Search | Solve |
| Maximum Number of Removable Characters | Medium | Binary Search | Solve |
| Minimize the Maximum Difference of Pairs | Medium | Binary Search | Solve |
| Search a 2D Matrix | Medium | Binary Search | Solve |
| Search in Rotated Sorted Array | Medium | Binary Search | Solve |
| Search In Rotated Sorted Array II | Medium | Binary Search | Solve |
| Search Suggestions System | Medium | Binary Search | Solve |
| Single Element in a Sorted Array | Medium | Binary Search | Solve |
| Successful Pairs of Spells and Potions | Medium | Binary Search | Solve |
| Time Based Key-Value Store | Medium | Binary Search | Solve |
| Allocate Books | Hard | Binary Search | Solve |
| Median of Two Sorted Arrays | Hard | Binary Search | Solve |
| Split Array Largest Sum | Hard | Binary Search | Solve |
Sorting
4Matrix
6Stack & Queue
23| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Baseball Game | Easy | Stack & Queue | Solve |
| Implement Stack Using Queues | Easy | Stack & Queue | Solve |
| Next Greater Element I | Easy | Stack & Queue | Solve |
| Valid Parentheses | Easy | Stack & Queue | Solve |
| 132 Pattern | Medium | Stack & Queue | Solve |
| Asteroid Collision | Medium | Stack & Queue | Solve |
| Car Fleet | Medium | Stack & Queue | Solve |
| Daily Temperatures | Medium | Stack & Queue | Solve |
| Decode String | Medium | Stack & Queue | Solve |
| Evaluate Reverse Polish Notation | Medium | Stack & Queue | Solve |
| Generate Parentheses | Medium | Stack & Queue | Solve |
| Min Stack | Medium | Stack & Queue | Solve |
| Next Greater Element II | Medium | Stack & Queue | Solve |
| Online Stock Span | Medium | Stack & Queue | Solve |
| Remove All Adjacent Duplicates In String II | Medium | Stack & Queue | Solve |
| Remove K Digits | Medium | Stack & Queue | Solve |
| Removing Stars From a String | Medium | Stack & Queue | Solve |
| Simplify Path | Medium | Stack & Queue | Solve |
| Sum of Subarray Minimums | Medium | Stack & Queue | Solve |
| Validate Stack Sequences | Medium | Stack & Queue | Solve |
| Largest Rectangle in Histogram | Hard | Stack & Queue | Solve |
| Maximal Rectangle | Hard | Stack & Queue | Solve |
| Maximum Frequency Stack | Hard | Stack & Queue | Solve |
Linked List
32| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Intersection of Two Linked Lists | Easy | Linked List | Solve |
| Linked List Cycle | Easy | Linked List | Solve |
| Merge Two Sorted Lists | Easy | Linked List | Solve |
| Middle of the Linked List | Easy | Linked List | Solve |
| Palindrome Linked List | Easy | Linked List | Solve |
| Remove Duplicates From Sorted List | Easy | Linked List | Solve |
| Remove Linked List Elements | Easy | Linked List | Solve |
| Reverse a Linked List | Easy | Linked List | Solve |
| Reverse Linked List | Easy | Linked List | Solve |
| Add Two Numbers | Medium | Linked List | Solve |
| Add Two Numbers II | Medium | Linked List | Solve |
| Copy List with Random Pointer | Medium | Linked List | Solve |
| Design Browser History | Medium | Linked List | Solve |
| Design Circular Queue | Medium | Linked List | Solve |
| Design Linked List | Medium | Linked List | Solve |
| Find The Duplicate Number | Medium | Linked List | Solve |
| Flatten a Multilevel Doubly Linked List | Medium | Linked List | Solve |
| Insertion Sort List | Medium | Linked List | Solve |
| LRU Cache | Medium | Linked List | Solve |
| Maximum Twin Sum Of A Linked List | Medium | Linked List | Solve |
| Partition List | Medium | Linked List | Solve |
| Remove Nth Node From End of List | Medium | Linked List | Solve |
| Reorder List | Medium | Linked List | Solve |
| Reverse Linked List II | Medium | Linked List | Solve |
| Rotate List | Medium | Linked List | Solve |
| Sort List | Medium | Linked List | Solve |
| Split Linked List in Parts | Medium | Linked List | Solve |
| Swap Nodes In Pairs | Medium | Linked List | Solve |
| Swapping Nodes in a Linked List | Medium | Linked List | Solve |
| LFU Cache | Hard | Linked List | Solve |
| Merge K Sorted Lists | Hard | Linked List | Solve |
| Reverse Nodes in k-Group | Hard | Linked List | Solve |
Recursion
5Backtracking
22| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Combination Sum | Medium | Backtracking | Solve |
| Combination Sum II | Medium | Backtracking | Solve |
| Combinations | Medium | Backtracking | Solve |
| Find Unique Binary String | Medium | Backtracking | Solve |
| Letter Combinations of a Phone Number | Medium | Backtracking | Solve |
| M-Coloring Problem | Medium | Backtracking | Solve |
| Matchsticks to Square | Medium | Backtracking | Solve |
| Maximum Length of a Concatenated String With Unique Characters | Medium | Backtracking | Solve |
| Palindrome Partitioning | Medium | Backtracking | Solve |
| Partition to K Equal Sum Subsets | Medium | Backtracking | Solve |
| Permutations | Medium | Backtracking | Solve |
| Permutations II | Medium | Backtracking | Solve |
| Rat in a Maze | Medium | Backtracking | Solve |
| Restore IP Addresses | Medium | Backtracking | Solve |
| Splitting a String Into Descending Consecutive Values | Medium | Backtracking | Solve |
| Subsets | Medium | Backtracking | Solve |
| Subsets II | Medium | Backtracking | Solve |
| Word Search | Medium | Backtracking | Solve |
| Expression Add Operators | Hard | Backtracking | Solve |
| N Queens II | Hard | Backtracking | Solve |
| N-Queens | Hard | Backtracking | Solve |
| Sudoku Solver | Hard | Backtracking | Solve |
Binary Trees
50| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Balanced Binary Tree | Easy | Binary Trees | Solve |
| Binary Tree Inorder Traversal | Easy | Binary Trees | Solve |
| Binary Tree Postorder Traversal | Easy | Binary Trees | Solve |
| Binary Tree Preorder Traversal | Easy | Binary Trees | Solve |
| Construct String From Binary Tree | Easy | Binary Trees | Solve |
| Convert Sorted Array to Binary Search Tree | Easy | Binary Trees | Solve |
| Diameter of Binary Tree | Easy | Binary Trees | Solve |
| Invert Binary Tree | Easy | Binary Trees | Solve |
| Maximum Depth of Binary Tree | Easy | Binary Trees | Solve |
| Merge Two Binary Trees | Easy | Binary Trees | Solve |
| Minimum Distance between BST Nodes | Easy | Binary Trees | Solve |
| Path Sum | Easy | Binary Trees | Solve |
| Same Tree | Easy | Binary Trees | Solve |
| Subtree of Another Tree | Easy | Binary Trees | Solve |
| Symmetric Tree | Easy | Binary Trees | Solve |
| All Possible Full Binary Trees | Medium | Binary Trees | Solve |
| Binary Search Tree Iterator | Medium | Binary Trees | Solve |
| Binary Tree Level Order Traversal | Medium | Binary Trees | Solve |
| Binary Tree Right Side View | Medium | Binary Trees | Solve |
| Binary Tree Zigzag Level Order Traversal | Medium | Binary Trees | Solve |
| Check Completeness of a Binary Tree | Medium | Binary Trees | Solve |
| Construct Binary Tree from Inorder and Postorder Traversal | Medium | Binary Trees | Solve |
| Construct Binary Tree from Preorder and Inorder | Medium | Binary Trees | Solve |
| Construct Binary Tree From Preorder And Inorder Traversal | Medium | Binary Trees | Solve |
| Construct Quad Tree | Medium | Binary Trees | Solve |
| Convert Bst to Greater Tree | Medium | Binary Trees | Solve |
| Count Complete Tree Nodes | Medium | Binary Trees | Solve |
| Count Good Nodes In Binary Tree | Medium | Binary Trees | Solve |
| Delete Node in a BST | Medium | Binary Trees | Solve |
| Find Bottom Left Tree Value | Medium | Binary Trees | Solve |
| Find Duplicate Subtrees | Medium | Binary Trees | Solve |
| Flatten Binary Tree to Linked List | Medium | Binary Trees | Solve |
| Flip Equivalent Binary Trees | Medium | Binary Trees | Solve |
| House Robber III | Medium | Binary Trees | Solve |
| Insert into a Binary Search Tree | Medium | Binary Trees | Solve |
| Kth Smallest Element In a Bst | Medium | Binary Trees | Solve |
| Lowest Common Ancestor of a Binary Search Tree | Medium | Binary Trees | Solve |
| Maximum Width of Binary Tree | Medium | Binary Trees | Solve |
| Minimum Time to Collect All Apples in a Tree | Medium | Binary Trees | Solve |
| Morris Inorder Traversal | Medium | Binary Trees | Solve |
| Operations On Tree | Medium | Binary Trees | Solve |
| Populating Next Right Pointers in Each Node | Medium | Binary Trees | Solve |
| Sum Root to Leaf Numbers | Medium | Binary Trees | Solve |
| Time Needed to Inform All Employees | Medium | Binary Trees | Solve |
| Trim a Binary Search Tree | Medium | Binary Trees | Solve |
| Unique Binary Search Trees | Medium | Binary Trees | Solve |
| Unique Binary Search Trees II | Medium | Binary Trees | Solve |
| Binary Tree Maximum Path Sum | Hard | Binary Trees | Solve |
| Serialize and Deserialize Binary Tree | Hard | Binary Trees | Solve |
| Vertical Order Traversal of a Binary Tree | Hard | Binary Trees | Solve |
BST
5Heaps
21| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Kth Largest Element in a Stream | Easy | Heaps | Solve |
| Last Stone Weight | Easy | Heaps | Solve |
| Car Pooling | Medium | Heaps | Solve |
| Design Twitter | Medium | Heaps | Solve |
| Find K Pairs with Smallest Sums | Medium | Heaps | Solve |
| Find The Kth Largest Integer In The Array | Medium | Heaps | Solve |
| K Closest Points to Origin | Medium | Heaps | Solve |
| Kth Largest Element in an Array | Medium | Heaps | Solve |
| Longest Happy String | Medium | Heaps | Solve |
| Maximum Subsequence Score | Medium | Heaps | Solve |
| Process Tasks Using Servers | Medium | Heaps | Solve |
| Reorganize String | Medium | Heaps | Solve |
| Seat Reservation Manager | Medium | Heaps | Solve |
| Single Threaded Cpu | Medium | Heaps | Solve |
| Task Scheduler | Medium | Heaps | Solve |
| Find Median from Data Stream | Hard | Heaps | Solve |
| IPO | Hard | Heaps | Solve |
| Maximum Performance of a Team | Hard | Heaps | Solve |
| Minimize Deviation in Array | Hard | Heaps | Solve |
| Minimum Number of Refueling Stops | Hard | Heaps | Solve |
| Trapping Rain Water II | Hard | Heaps | Solve |
Tries
7| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Longest Common Prefix | Easy | Tries | Solve |
| Count Distinct Substrings using Trie | Medium | Tries | Solve |
| Design Add and Search Words Data Structure | Medium | Tries | Solve |
| Extra Characters in a String | Medium | Tries | Solve |
| Implement Trie (Prefix Tree) | Medium | Tries | Solve |
| Maximum XOR of Two Numbers in an Array | Medium | Tries | Solve |
| Word Search II | Hard | Tries | Solve |
Graphs
60| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Island Perimeter | Easy | Graphs | Solve |
| Verifying An Alien Dictionary | Easy | Graphs | Solve |
| Accounts Merge | Medium | Graphs | Solve |
| As Far from Land as Possible | Medium | Graphs | Solve |
| Bellman-Ford Algorithm | Medium | Graphs | Solve |
| Bipartite Graph Check | Medium | Graphs | Solve |
| Cheapest Flights Within K Stops | Medium | Graphs | Solve |
| Check if Move Is Legal | Medium | Graphs | Solve |
| Clone Graph | Medium | Graphs | Solve |
| Count Sub Islands | Medium | Graphs | Solve |
| Course Schedule | Medium | Graphs | Solve |
| Course Schedule II | Medium | Graphs | Solve |
| Course Schedule IV | Medium | Graphs | Solve |
| Detonate the Maximum Bombs | Medium | Graphs | Solve |
| Disjoint Set Union (DSU) | Medium | Graphs | Solve |
| Evaluate Division | Medium | Graphs | Solve |
| Find Closest Node to Given Two Nodes | Medium | Graphs | Solve |
| Find Eventual Safe States | Medium | Graphs | Solve |
| Floyd-Warshall Algorithm | Medium | Graphs | Solve |
| Graph Valid Tree | Medium | Graphs | Solve |
| Is Graph Bipartite? | Medium | Graphs | Solve |
| Max Area of Island | Medium | Graphs | Solve |
| Min Cost to Connect All Points | Medium | Graphs | Solve |
| Minimum Fuel Cost to Report to the Capital | Medium | Graphs | Solve |
| Minimum Number of Vertices to Reach all Nodes | Medium | Graphs | Solve |
| Minimum Score of a Path Between Two Cities | Medium | Graphs | Solve |
| Minimum Spanning Tree - Kruskal's | Medium | Graphs | Solve |
| Minimum Spanning Tree - Prim's | Medium | Graphs | Solve |
| Network Delay Time | Medium | Graphs | Solve |
| Number of Closed Islands | Medium | Graphs | Solve |
| Number of Connected Components In An Undirected Graph | Medium | Graphs | Solve |
| Number of Connected Components in Undirected Graph | Medium | Graphs | Solve |
| Number of Enclaves | Medium | Graphs | Solve |
| Number of Islands | Medium | Graphs | Solve |
| Open The Lock | Medium | Graphs | Solve |
| Pacific Atlantic Water Flow | Medium | Graphs | Solve |
| Path with Maximum Probability | Medium | Graphs | Solve |
| Path with Minimum Effort | Medium | Graphs | Solve |
| Redundant Connection | Medium | Graphs | Solve |
| Reorder Routes to Make All Paths Lead to The City Zero | Medium | Graphs | Solve |
| Rotting Oranges | Medium | Graphs | Solve |
| Shortest Bridge | Medium | Graphs | Solve |
| Shortest Path in Binary Matrix | Medium | Graphs | Solve |
| Shortest Path with Alternating Colors | Medium | Graphs | Solve |
| Snakes And Ladders | Medium | Graphs | Solve |
| Surrounded Regions | Medium | Graphs | Solve |
| Walls and Gates | Medium | Graphs | Solve |
| Alien Dictionary | Hard | Graphs | Solve |
| Articulation Points | Hard | Graphs | Solve |
| Bridges in a Graph | Hard | Graphs | Solve |
| Find Critical and Pseudo Critical Edges in Minimum Spanning Tree | Hard | Graphs | Solve |
| Largest Color Value in a Directed Graph | Hard | Graphs | Solve |
| Making a Large Island | Hard | Graphs | Solve |
| Minimum Number of Days to Eat N Oranges | Hard | Graphs | Solve |
| Number of Good Paths | Hard | Graphs | Solve |
| Reconstruct Itinerary | Hard | Graphs | Solve |
| Remove Max Number of Edges to Keep Graph Fully Traversable | Hard | Graphs | Solve |
| Strongly Connected Components - Kosaraju's | Hard | Graphs | Solve |
| Swim in Rising Water | Hard | Graphs | Solve |
| Word Ladder | Hard | Graphs | Solve |
Intervals
2Segment Tree
3Fenwick Tree
2Dynamic Programming
68| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Climbing Stairs | Easy | Dynamic Programming | Solve |
| Min Cost Climbing Stairs | Easy | Dynamic Programming | Solve |
| N-th Tribonacci Number | Easy | Dynamic Programming | Solve |
| Best Team with no Conflicts | Medium | Dynamic Programming | Solve |
| Best Time to Buy and Sell Stock with Cooldown | Medium | Dynamic Programming | Solve |
| Best Time to Buy and Sell Stock with Transaction Fee | Medium | Dynamic Programming | Solve |
| Check if There is a Valid Partition For The Array | Medium | Dynamic Programming | Solve |
| Coin Change | Medium | Dynamic Programming | Solve |
| Coin Change II | Medium | Dynamic Programming | Solve |
| Combination Sum IV | Medium | Dynamic Programming | Solve |
| Count Ways to Build Good Strings | Medium | Dynamic Programming | Solve |
| Decode Ways | Medium | Dynamic Programming | Solve |
| Delete And Earn | Medium | Dynamic Programming | Solve |
| Edit Distance | Medium | Dynamic Programming | Solve |
| Flip String to Monotone Increasing | Medium | Dynamic Programming | Solve |
| House Robber | Medium | Dynamic Programming | Solve |
| House Robber II | Medium | Dynamic Programming | Solve |
| Integer Break | Medium | Dynamic Programming | Solve |
| Interleaving String | Medium | Dynamic Programming | Solve |
| Jump Game VII | Medium | Dynamic Programming | Solve |
| Last Stone Weight II | Medium | Dynamic Programming | Solve |
| Longest Common Subsequence | Medium | Dynamic Programming | Solve |
| Longest Increasing Subsequence | Medium | Dynamic Programming | Solve |
| Longest Palindromic Subsequence | Medium | Dynamic Programming | Solve |
| Maximal Square | Medium | Dynamic Programming | Solve |
| Maximum Alternating Subsequence Sum | Medium | Dynamic Programming | Solve |
| Maximum Subarray Min Product | Medium | Dynamic Programming | Solve |
| Maximum Sum Increasing Subsequence | Medium | Dynamic Programming | Solve |
| Minimum Cost For Tickets | Medium | Dynamic Programming | Solve |
| Minimum Path Sum | Medium | Dynamic Programming | Solve |
| New 21 Game | Medium | Dynamic Programming | Solve |
| Number of Longest Increasing Subsequence | Medium | Dynamic Programming | Solve |
| Ones and Zeroes | Medium | Dynamic Programming | Solve |
| Paint House | Medium | Dynamic Programming | Solve |
| Partition Equal Subset Sum | Medium | Dynamic Programming | Solve |
| Perfect Squares | Medium | Dynamic Programming | Solve |
| Solving Questions With Brainpower | Medium | Dynamic Programming | Solve |
| Stone Game | Medium | Dynamic Programming | Solve |
| Stone Game II | Medium | Dynamic Programming | Solve |
| Target Sum | Medium | Dynamic Programming | Solve |
| Triangle | Medium | Dynamic Programming | Solve |
| Uncrossed Lines | Medium | Dynamic Programming | Solve |
| Unique Paths | Medium | Dynamic Programming | Solve |
| Unique Paths II | Medium | Dynamic Programming | Solve |
| Word Break | Medium | Dynamic Programming | Solve |
| Best Time to Buy and Sell Stock III | Hard | Dynamic Programming | Solve |
| Best Time to Buy and Sell Stock IV | Hard | Dynamic Programming | Solve |
| Burst Balloons | Hard | Dynamic Programming | Solve |
| Concatenated Words | Hard | Dynamic Programming | Solve |
| Count all Valid Pickup and Delivery Options | Hard | Dynamic Programming | Solve |
| Count Vowels Permutation | Hard | Dynamic Programming | Solve |
| Distinct Subsequences | Hard | Dynamic Programming | Solve |
| Find the Longest Valid Obstacle Course at Each Position | Hard | Dynamic Programming | Solve |
| Longest Increasing Path in a Matrix | Hard | Dynamic Programming | Solve |
| Matrix Chain Multiplication | Hard | Dynamic Programming | Solve |
| Maximize Score after N Operations | Hard | Dynamic Programming | Solve |
| Maximum Value of K Coins from Piles | Hard | Dynamic Programming | Solve |
| Minimum Cost to Cut a Stick | Hard | Dynamic Programming | Solve |
| Minimum Edit Distance | Hard | Dynamic Programming | Solve |
| Number of Music Playlists | Hard | Dynamic Programming | Solve |
| Number of Ways to Form a Target String Given a Dictionary | Hard | Dynamic Programming | Solve |
| Number of Ways to Rearrange Sticks With K Sticks Visible | Hard | Dynamic Programming | Solve |
| Palindrome Partitioning II | Hard | Dynamic Programming | Solve |
| Profitable Schemes | Hard | Dynamic Programming | Solve |
| Regular Expression Matching | Hard | Dynamic Programming | Solve |
| Stickers to Spell Word | Hard | Dynamic Programming | Solve |
| Stone Game III | Hard | Dynamic Programming | Solve |
| Wildcard Matching | Hard | Dynamic Programming | Solve |
Greedy
24| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Meeting Rooms | Easy | Greedy | Solve |
| Activity Selection Problem | Medium | Greedy | Solve |
| Dota2 Senate | Medium | Greedy | Solve |
| Eliminate Maximum Number of Monsters | Medium | Greedy | Solve |
| Fractional Knapsack | Medium | Greedy | Solve |
| Gas Station | Medium | Greedy | Solve |
| Hand of Straights | Medium | Greedy | Solve |
| Jump Game | Medium | Greedy | Solve |
| Jump Game II | Medium | Greedy | Solve |
| Longest Turbulent Array | Medium | Greedy | Solve |
| Maximum Length of Pair Chain | Medium | Greedy | Solve |
| Maximum Meetings in One Room | Medium | Greedy | Solve |
| Maximum Sum Circular Subarray | Medium | Greedy | Solve |
| Meeting Rooms II | Medium | Greedy | Solve |
| Merge Triplets to Form Target Triplet | Medium | Greedy | Solve |
| Minimize Maximum of Array | Medium | Greedy | Solve |
| Minimum Deletions to Make Character Frequencies Unique | Medium | Greedy | Solve |
| Minimum Number of Arrows to Burst Balloons | Medium | Greedy | Solve |
| Non-overlapping Intervals | Medium | Greedy | Solve |
| Partition Labels | Medium | Greedy | Solve |
| Two City Scheduling | Medium | Greedy | Solve |
| Valid Parenthesis String | Medium | Greedy | Solve |
| Candy | Hard | Greedy | Solve |
| Minimum Interval to Include Each Query | Hard | Greedy | Solve |
Bit Manipulation
13| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Add Binary | Easy | Bit Manipulation | Solve |
| Add to Array-Form of Integer | Easy | Bit Manipulation | Solve |
| Counting Bits | Easy | Bit Manipulation | Solve |
| Missing Number | Easy | Bit Manipulation | Solve |
| Number of 1 Bits | Easy | Bit Manipulation | Solve |
| Power of Two | Easy | Bit Manipulation | Solve |
| Reverse Bits | Easy | Bit Manipulation | Solve |
| Shuffle the Array | Easy | Bit Manipulation | Solve |
| Single Number | Easy | Bit Manipulation | Solve |
| Reverse Integer | Medium | Bit Manipulation | Solve |
| Single Number II | Medium | Bit Manipulation | Solve |
| Sum of Two Integers | Medium | Bit Manipulation | Solve |
| XOR Queries of a Subarray | Medium | Bit Manipulation | Solve |
Math
20| Problem | Difficulty | Topic | Practice |
|---|---|---|---|
| Count Odd Numbers in an Interval Range | Easy | Math | Solve |
| Excel Sheet Column Number | Easy | Math | Solve |
| Excel Sheet Column Title | Easy | Math | Solve |
| Greatest Common Divisor of Strings | Easy | Math | Solve |
| Happy Number | Easy | Math | Solve |
| Matrix Diagonal Sum | Easy | Math | Solve |
| Palindrome Number | Easy | Math | Solve |
| Plus One | Easy | Math | Solve |
| Roman to Integer | Easy | Math | Solve |
| Shift 2D Grid | Easy | Math | Solve |
| Sqrt(x) | Easy | Math | Solve |
| Ugly Number | Easy | Math | Solve |
| Count Primes | Medium | Math | Solve |
| Detect Squares | Medium | Math | Solve |
| Find Missing Observations | Medium | Math | Solve |
| Integer to Roman | Medium | Math | Solve |
| Multiply Strings | Medium | Math | Solve |
| Pow(x, n) | Medium | Math | Solve |
| Robot Bounded In Circle | Medium | Math | Solve |
| Maximum Points on a Line | Hard | Math | Solve |