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 |
|---|---|---|---|
| 201 | Search In Rotated Sorted Array Array · Searching Algorithms | 37.64% | Medium |
| 202 | Form Anagram Groups String · Hashing | 69.80% | Medium |
| 203 | Longest Common Prefix Array · String | 44.20% | Easy |
| 204 | Count Inversions Array · Sorting Algorithms | 16.93% | Medium |
| 205 | 2Sum - Pair With Given Sum Array · Hashing · Hashmap | 30.61% | Easy |
| 206 | Maximize Number of 1's Array · Binary Search | 50.00% | Medium |
| 207 | Combination Sum Recursion | 75.00% | Medium |
| 208 | Print Numbers from 1 to N Recursion | 75.00% | Easy |
| 209 | Print Number From N to 1 Recursion | 80.00% | Easy |
| 210 | Sum Of First N Natural Numbers Recursion | 60.00% | Easy |
| 211 | Largest subarray of 0's and 1's Data Structures Basics | 50.00% | Easy |
| 212 | Max of min for every window Stack | 50.00% | Hard |
| 213 | Maximum fruit gathering by birds Array | 50.00% | Easy |
| 214 | Sum of elements of smallest subarray greater than x Array | 50.00% | Easy |
| 215 | Length of the longest substring String | 50.00% | Medium |
| 216 | Smallest Window of All Characters String · Dynamic Programming | 50.00% | Hard |
| 217 | Equal Sum Subarrays Queue | 50.00% | Easy |
| 218 | Ways to Reaching the n'th Stair Dynamic Programming | 50.00% | Medium |
| 219 | Implement Min Stack Stack | 22.59% | Medium |
| 220 | First non-repeating in a stream Queue | 31.65% | Medium |
| 221 | Binary Heap Operations Heap | 22.30% | Medium |
| 222 | Detect Loop in linked list Linked List | 43.49% | Medium |
| 223 | Palindrome Linked List Linked List | 41.48% | Medium |
| 224 | Categorize even and odd nodes in a Linked List Linked List | 49.80% | Medium |
| 225 | Check for balanced Paranthesis Stack | 28.56% | Easy |
| 226 | Asteroid Collision Stack | 50.06% | Medium |
| 227 | Convert Infix To Prefix Notation Stack | 52.94% | Medium |
| 228 | Histogram Max Rectangular Area Stack | 32.12% | Hard |
| 229 | Implement Queue using Arrays Queue | 47.24% | Basic |
| 230 | Minimum Cost of Ropes Queue | 42.73% | Medium |
| 231 | Heap Sort Heap | 53.06% | Medium |
| 232 | Word Search Recursion | 32.69% | Medium |
| 233 | Print Pattern Recursion | 56.39% | Easy |
| 234 | Floor in a Sorted Array Sorting Algorithms | 33.75% | Easy |
| 235 | Minimum sum Array · Sorting Algorithms | 17.14% | Medium |
| 236 | Number of Pairs Array | 21.82% | Medium |
| 237 | Find Transition Point Array · Searching Algorithms | 37.90% | Easy |
| 238 | Super Primes Searching Algorithms | 24.90% | Medium |
| 239 | Pair Sum Closest to 0 Searching Algorithms | 19.61% | Easy |
| 240 | Bitonic Point Searching Algorithm | 58.67% | Easy |
| 241 | Alien Dictionary String | 47.81% | Hard |
| 242 | Find the String String | 72.98% | Hard |
| 243 | 0-1 Knapsack Problem Array · Dynamic Programming | 50.00% | Medium |
| 244 | Rod Cutting Array · Dynamic Programming | 50.00% | Medium |
| 245 | Stock buy and sell Array · Dynamic Programming | 29.18% | Medium |
| 246 | Maximum Meetings in One Room Array · Sorting Algorithms | 33.57% | Medium |
| 247 | Subset Sums Recursion | 72.55% | Medium |
| 248 | Interleave the First Half of the Queue with Second Half Queue | 69.35% | Medium |
| 249 | Merge Sort for Linked List Linked List | 74.76% | Medium |
| 250 | Reverse a Linked List in Groups Linked List | 57.08% | 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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