Think in patterns.
Solve like it’s the interview.
hand-picked DSA problems in C#, Java, Python, C++ and JavaScript. Run your code, climb the leaderboard and keep your streak alive.
- 297problems
- 12core patterns
- 5languages
- 2 Lakh+learners trained
Bubble sort
ArraysO(n²)Running
Compare neighbours, swap when out of order.
Inorder traversal
TreesDFSO(n)
Visit order:
Breadth-first search
GraphsQueueO(V+E)
Level order:
Longest common subsequence
Dynamic ProgrammingO(mn)
dp[i][j] = best length for the first i and j characters.
Browse by pattern
Master the idea once, solve the whole family.
| # | Title | Acceptance | Difficulty |
|---|---|---|---|
| 101 | Search / Insert into BST Tree · Traversal · Binary Tree | 89.54% | Easy |
| 102 | Find Nodes at Distance K from Given Node Tree · Traversal · Binary Tree | 65.95% | Hard |
| 103 | Lowest Common Ancestor of Binary Tree Tree · Traversal · Binary Tree | 78.59% | Medium |
| 104 | Print All Root To Leaf Paths Tree · Traversal · Binary Tree | 68.59% | Hard |
| 105 | Root To Leaf Path Sum Tree · Traversal · Binary Tree | 78.56% | Medium |
| 106 | Diameter of Binary Tree Tree · Traversal · Binary Tree | 73.45% | Medium |
| 107 | Check Binary Tree Is Balanced Tree · Traversal · Binary Tree | 78.95% | Medium |
| 108 | Check if Tree is Symmetric Tree · Traversal · Binary Tree | 74.98% | Medium |
| 109 | Check if Two Trees are Identical Tree · Traversal · Binary Tree | 76.59% | Medium |
| 110 | Count Leaf Nodes In Binary Tree Tree · Traversal · Binary Tree | 74.59% | Medium |
| 111 | Count Total Nodes in Binary Tree Tree · Traversal · Binary Tree | 75.68% | Medium |
| 112 | Height / Max Depth of Binary Tree Tree · Traversal · Binary Tree | 75.36% | Medium |
| 113 | Binary Tree Zigzag Level Order Traversal Tree · Recursion · Traversal | 71.48% | Medium |
| 114 | Binary Tree Level Order Traversal Tree · Recursion · Traversal | 79.68% | Easy |
| 115 | Binary Tree Inorder Traversal Recursion · Trees · Traversal | 75.68% | Easy |
| 116 | Binary Tree Preorder Traversal Tree · Recursion · Binary Tree | 79.85% | Easy |
| 117 | Intersection of Two Linked Lists Linked List | 75.00% | Medium |
| 118 | Sort A Linked List (Merge Sort) Linked List | 58.00% | Medium |
| 119 | Merge K Sorted Lists Linked List | 70.00% | Medium |
| 120 | Merge Two Sorted Linked Lists Link List | 59.00% | Medium |
| 121 | Swap Nodes in Pairs Linked List | 65.00% | Medium |
| 122 | Reverse Sublist (Between Left & Right) Linked List | 67.00% | Medium |
| 123 | Reverse Linked List in K Groups Linked List | 60.00% | Medium |
| 124 | Reverse Linked List in Pairs Linked List | 63.00% | Medium |
| 125 | Kth Smallest Pair Distance Binary Search | 65.00% | Medium |
| 126 | Find K Closest Elements Binary Search | 76.00% | Medium |
| 127 | Kth Smallest Element In A Matrix Binary Search | 70.00% | Medium |
| 128 | Remove Nth Node From End Linked List | 73.00% | Medium |
| 129 | Check if Linked List is Palindrome Linked List | 67.00% | Medium |
| 130 | Detect Cycle In Linked List Linked List | 65.00% | Medium |
| 131 | Find Start of Cycle Linked List | 57.00% | Medium |
| 132 | Reverse A Linked List Linked List | 79.00% | Easy |
| 133 | Length of Linked List Linked List | 76.00% | Easy |
| 134 | Nth Node From End Linked List | 69.00% | Medium |
| 135 | Find Middle of Linked List Linked List | 87.00% | Easy |
| 136 | Kth Smallest In Multiplication Table Binary Search | 75.00% | Medium |
| 137 | Square Root of A Number Binary Search | 63.00% | Medium |
| 138 | Median Of Two Sorted Arrays Binary Search | 71.00% | Medium |
| 139 | Lower Bound Binary Search | 75.00% | Medium |
| 140 | Magnetic Force Between Two Balls Binary Search | 60.00% | Medium |
| 141 | Find Smallest Divisor Given A Threshold Binary Search | 67.00% | Medium |
| 142 | Minimise Maximum Distance To Go To Gas Station Binary Search | 64.00% | Medium |
| 143 | Capacity To Ship Packages Within D Days Binary Search | 65.00% | Medium |
| 144 | Median In Row-Wise Sorted Array Binary Search | 69.00% | Medium |
| 145 | Search in A Sorted 2D Matrix II Binary Search | 70.00% | Medium |
| 146 | Search in a 2D Matrix Recursion · Binary Search | 86.00% | Medium |
| 147 | Split Array Largest Sum Binary Search | 59.00% | Medium |
| 148 | Find Minimum In Rotated Sorted Array Recursion | 89.00% | Medium |
| 149 | Aggressive Cows Binary Search | 70.00% | Medium |
| 150 | Allocate Minimum Pages Binary Search | 62.00% | Medium |
Practice that builds the habit
Three steps, repeated every day.
- 1
Pick a pattern
Start from an idea such as two pointers or BFS, then move through easy, medium and hard.
- 2
Code and run
Write in your language, run on sample cases and submit against every hidden test.
- 3
Climb the board
Every solve earns points. Keep a daily streak and see where you stand this month.
Want a plan, not just problems?
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