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 |
|---|---|---|---|
| 1 | Find the Largest Power of 2 That Divides N! Introduction · Data Structures Basics · Basics | 96.85% | Basic |
| 2 | Find the Number of Trailing Zeroes in N! Introduction · Data Structures Basics · Basics | 83.63% | Basic |
| 3 | Calculate a^b Using Exponentiation by Squaring Data Structures Basics · Searching Algorithms · Sorting Algorithms | 86.53% | Basic |
| 4 | Find the Missing Term in a Geometric Progression Introduction · Data Structures Basics · Array | 88.72% | Basic |
| 5 | Check Whether Three Numbers Form an Arithmetic Progression Data Structures Basics | 73.03% | Basic |
| 6 | Find the Missing Term in an Arithmetic Progression Introduction · Data Structures Basics · Array | 82.87% | Basic |
| 7 | Find the Sum of Fibonacci Numbers in a Range Introduction · Data Structures Basics | 84.68% | Basic |
| 8 | Check Whether a Number Belongs to the Fibonacci Sequence Data Structures Basics · Basics | 74.95% | Basic |
| 9 | Find the Nth Fibonacci Number Efficiently Data Structures Basics · Recursion · Dynamic Programming | 85.25% | Basic |
| 10 | Generate Fibonacci Numbers up to a Limit Data Structures Basics | 81.42% | Basic |
| 11 | Diamond Pattern Data Structures Basics · String | 94.13% | Basic |
| 12 | Find All Perfect Numbers in a Range Data Structures Basics | 82.42% | Basic |
| 13 | Check Whether a Number Is Perfect Data Structures Basics | 78.12% | Basic |
| 14 | Check Whether a Number Is Strong Data Structures Basics · Basics | 66.91% | Basic |
| 15 | Find All Armstrong Numbers in a Range Data Structures Basics · Basics | 89.12% | Basic |
| 16 | Check Whether a Number Is Armstrong Data Structures Basics · Basics | 79.84% | Basic |
| 17 | Find the Number Below N Having the Maximum Number of Divisors Data Structures Basics · Basics | 87.33% | Basic |
| 18 | Find GCD of Multiple Numbers Data Structures Basics · Array · Basics | 98.77% | Basic |
| 19 | Find All Numbers Having Exactly K Divisors Data Structures Basics · Searching Algorithms · Basics | 77.99% | Basic |
| 20 | Find LCM of Multiple Numbers Data Structures Basics · Array · Basics | 87.89% | Basic |
| 21 | Find the Sum of Divisors Data Structures Basics · Hash Table | 78.12% | Basic |
| 22 | Check Whether Two Numbers Are Coprime Data Structures Basics · Comparisons | 83.45% | Basic |
| 23 | Find the Number of Divisors of a Number Data Structures Basics · Basics | 87.65% | Basic |
| 24 | Count Total Prime Factors Including Repetitions Data Structures Basics · Hashing · Basics | 87.32% | Basic |
| 25 | Count Distinct Prime Factors Data Structures Basics · Hashing · Basics | 87.32% | Basic |
| 26 | Find the Largest Prime Factor Data Structures Basics · Basics | 73.38% | Basic |
| 27 | Find All Prime Factors of a Number Data Structures Basics · Basics | 75.67% | Basic |
| 28 | Find the Next Prime Number Data Structures Basics · Basics | 100.00% | Basic |
| 29 | Find the Nth Prime Number Data Structures Basics · Searching Algorithm · Basics | 84.00% | Basic |
| 30 | Check Whether a Number Is Prime Using vN Optimization Data Structures Basics · Basics | 99.99% | Basic |
| 31 | Find All Primes in a Range Data Structures Basics · Searching Algorithm · Basics | 98.24% | Basic |
| 32 | Check Whether a Number Is a Kaprekar Number Data Structures Basics | 88.00% | Basic |
| 33 | Check Whether a Number Is a Happy Number Data Structures Basics | 85.46% | Basic |
| 34 | Find the Digital Root Data Structures Basics | 81.53% | Basic |
| 35 | Find the Longest Increasing Sequence of Digits Data Structures Basics | 76.65% | Basic |
| 36 | Find the Longest Consecutive Sequence of the Same Digit Data Structures Basics · Array · String | 84.75% | Basic |
| 37 | Check Whether Digits Alternate in Parity Data Structures Basics · String · Searching Algorithms | 78.04% | Basic |
| 38 | Check Whether Digits Are Strictly Decreasing Data Structures Basics · String · Searching Algorithms | 87.15% | Basic |
| 39 | Check Whether Digits Are Strictly Increasing Data Structures Basics · Searching Algorithms | 96.12% | Basic |
| 40 | Swap the First and Last Digits of a Number Data Structures Basics · String | 78.12% | Basic |
| 41 | Remove Duplicate Digits While Preserving Order Data Structures Basics | 78.19% | Basic |
| 42 | Remove All Occurrences of a Digit Data Structures Basics · Array · String | 78.62% | Basic |
| 43 | Check Whether All Digits Are Distinct Data Structures Basics · String · Searching Algorithms | 79.18% | Basic |
| 44 | Count Distinct Digits in a Number Data Structures Basics · Basics | 91.32% | Basic |
| 45 | Find the Most Frequent Digit Data Structures Basics · Searching Algorithms | 84.69% | Basic |
| 46 | Find the Smallest and Second-Smallest Distinct Digits Data Structures Basics · Searching Algorithms | 91.98% | Basic |
| 47 | Find the Second Smallest of Four Numbers Data Structures Basics · Array · Sorting Algorithms | 89.85% | Basic |
| 48 | Find the Middle Value Among Three Distinct Numbers Data Structures Basics · Comparisons | 84.12% | Basic |
| 49 | Sort Three Numbers Using Conditional Statements Data Structures Basics · Comparisons | 90.15% | Basic |
| 50 | Reverse Digits of a Number Data Structures Basics | 89.81% | Basic |
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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