DSA coding practice problems
Practise data structures and algorithms on more than 1,500 problems with hidden tests, editorials and hints in 13 languages. Read any problem free.
What are CodeKairo's coding challenges?
CodeKairo's challenges are more than 1,500 data-structures-and-algorithms problems — roughly 490 easy, 800 medium and 300 hard — each with a typed function signature, starter code in 13 languages (JavaScript, TypeScript, Python, Java, C++, C, C#, Go, Kotlin, Swift, Rust, PHP and Ruby), visible sample cases and hidden tests that decide the verdict. Most carry progressive hints and an editorial. Any problem can be read without an account; running and submitting code needs a free one, and solving is unlimited on every plan.
Browse by topic
- Arrays 1199 problems · 320 easy · 633 medium · 246 hard
- Strings 515 problems · 185 easy · 241 medium · 89 hard
- Hash Table 439 problems · 134 easy · 250 medium · 55 hard
- Dynamic Programming 402 problems · 11 easy · 208 medium · 183 hard
- Math 337 problems · 123 easy · 151 medium · 63 hard
- Sorting 274 problems · 67 easy · 155 medium · 52 hard
- Greedy 264 problems · 43 easy · 174 medium · 47 hard
- Depth-First Search 201 problems · 37 easy · 127 medium · 37 hard
- Binary Search 189 problems · 24 easy · 115 medium · 50 hard
- Matrix 184 problems · 32 easy · 102 medium · 50 hard
- Two Pointers 165 problems · 61 easy · 90 medium · 14 hard
- Breadth-First Search 156 problems · 19 easy · 95 medium · 42 hard
- Trees 155 problems · 43 easy · 92 medium · 20 hard
- Bit Manipulation 146 problems · 38 easy · 67 medium · 41 hard
- Prefix Sum 137 problems · 19 easy · 85 medium · 33 hard
- Simulation 137 problems · 66 easy · 66 medium · 5 hard
- Counting 118 problems · 47 easy · 63 medium · 8 hard
- Stack 111 problems · 22 easy · 64 medium · 25 hard
- Graph 107 problems · 5 easy · 60 medium · 42 hard
- Heap 106 problems · 8 easy · 63 medium · 35 hard
- Sliding Window 103 problems · 17 easy · 62 medium · 24 hard
- Backtracking 62 problems · 3 easy · 43 medium · 16 hard
- Union Find 59 problems · 1 easy · 37 medium · 21 hard
- Enumeration 55 problems · 17 easy · 29 medium · 9 hard
- Number Theory 48 problems · 14 easy · 19 medium · 15 hard
- Monotonic Stack 45 problems · 2 easy · 27 medium · 16 hard
- Recursion 40 problems · 9 easy · 19 medium · 12 hard
- Ordered Set 32 problems · 1 easy · 17 medium · 14 hard
- Bitmask 29 problems · 8 medium · 21 hard
- Divide and Conquer 27 problems · 4 easy · 14 medium · 9 hard
- Queue 27 problems · 6 easy · 13 medium · 8 hard
- Trie 27 problems · 1 easy · 16 medium · 10 hard
- Combinatorics 25 problems · 2 easy · 10 medium · 13 hard
- Geometry 22 problems · 7 easy · 10 medium · 5 hard
- Memoization 21 problems · 2 easy · 5 medium · 14 hard
- Shortest Path 21 problems · 13 medium · 8 hard
- Game Theory 19 problems · 3 easy · 11 medium · 5 hard
- Topological Sort 19 problems · 9 medium · 10 hard
- Rolling Hash 17 problems · 6 medium · 11 hard
- String Matching 14 problems · 6 easy · 3 medium · 5 hard
- Binary Indexed Tree 12 problems · 6 medium · 6 hard
- Brainteaser 12 problems · 3 easy · 9 medium
- Monotonic Queue 12 problems · 5 medium · 7 hard
- Segment Tree 12 problems · 4 medium · 8 hard
- Intervals 11 problems · 1 easy · 9 medium · 1 hard
- Counting Sort 8 problems · 6 easy · 2 medium
- Digit DP 7 problems · 7 hard
- Minimum Spanning Tree 4 problems · 3 medium · 1 hard
- Merge Sort 3 problems · 1 medium · 2 hard
- Quickselect 3 problems · 3 medium
- Biconnected Component 2 problems · 2 hard
- Bucket Sort 2 problems · 2 medium
- KMP Algorithm 2 problems · 2 hard
- Sieve of Eratosthenes 1 problems · 1 medium
- Suffix Array 1 problems · 1 hard
Browse by company
- Amazon 1812 problems
- Google 1309 problems
- Microsoft 449 problems
- Adobe 225 problems
- Meta 223 problems
- TCS 124 problems
- Infosys 83 problems
- Bloomberg 79 problems
- Uber 68 problems
- Flipkart 63 problems
- Wipro 40 problems
- Zoho 37 problems
- Apple 33 problems
- Accenture 29 problems
- Morgan Stanley 29 problems
- Airbnb 26 problems
- Capgemini 26 problems
- Atlassian 25 problems
- Cognizant 25 problems
- Intuit 25 problems
- Twitter 25 problems
- Capital One 24 problems
- Databricks 24 problems
- Nutanix 24 problems
- Samsung 24 problems
- Snapchat 24 problems
- Zomato 24 problems
- PhonePe 23 problems
- Sprinklr 23 problems
- Myntra 22 problems
- Yahoo 22 problems
- Yelp 22 problems
- MathWorks 21 problems
- Ola 20 problems
- Rubrik 20 problems
- HCL 19 problems
- Indeed 19 problems
- LinkedIn 19 problems
- Mindtree 19 problems
- Palantir 19 problems
- Directi 18 problems
- Oracle 17 problems
- Spotify 17 problems
- Arcesium 16 problems
- Paytm 16 problems
- Two Sigma 16 problems
- Epic Systems 15 problems
- Dream11 14 problems
- Goldman Sachs 14 problems
- Razorpay 14 problems
- Dropbox 13 problems
- Mphasis 13 problems
- Virtusa 13 problems
- Salesforce 12 problems
- Tech Mahindra 12 problems
- Walmart 12 problems
- Hotstar 11 problems
- Freshworks 10 problems
- Hulu 10 problems
- Swiggy 10 problems
- LiveRamp 9 problems
- CRED 6 problems
- Riot Games 6 problems
2099 problems in the catalogue. The DSA roadmap orders about 150 of them into 19 stages; the daily contest picks one a day.
How it works
- Pick a problem. Filter by difficulty, topic, company or status, or take the shuffled default. Each problem page shows the statement, constraints and sample cases.
- Write it in your language. The editor opens with the starter signature for whichever of the 13 languages you choose. Drafts autosave per problem and language.
- Run, then Submit. Run checks the sample cases and any custom cases you add, with your output beside the expected one. Submit runs the hidden tests and records one verdict — Accepted, Wrong Answer, Time Limit Exceeded or Runtime Error — with cases passed, runtime and memory.
- Accepted counts. A first accepted submission pays XP by difficulty, moves your rating, marks the day for your streak and advances the DSA roadmap if the problem is on it.
Who it is for
Anyone practising for a coding round: the filters cover difficulty, topic, company tag and whether you have solved it, so a beginner can start on easy arrays and an interview candidate can work through a company's tagged problems.