35 curated challenges across topics, patterns, difficulty levels, and more. Each has a leaderboard.
Master DP patterns: knapsack, LCS, coins, paths & more
Conquer search on sorted arrays, rotations, and answer spaces
BFS, DFS, shortest paths, topological sort, and cycles
Binary trees, BST operations, traversals, and tree DP
Make locally optimal choices to achieve globally optimal results
Fixed & variable windows on arrays and strings
Two-pointer and fast/slow pointer techniques
Explore all possibilities with recursive state-space search
Monotonic stacks, deques, and queue-based simulations
Hash maps, sets, frequency counts, and anagram tricks
Merge sort, quick sort, counting sort, and sort-based tricks
XOR tricks, bit masks, counting bits, and bitwise ops
Substrings, palindromes, pattern matching, and string DP
GCD, primes, modular arithmetic, and combinatorics
Reversals, cycle detection, merge, and pointer manipulation
A quick 7-problem sprint to ignite your problem-solving
One month, 30 problems — build a solid coding habit
45 problems spanning all key DSA domains
Two months of consistent practice across all difficulty levels
The ultimate 3-month journey to interview mastery
Range sum queries, subarrays, and difference arrays
Next greater element, largest rectangle, and stock span
Disjoint set union for connected components and Kruskal's
Word search, autocomplete, and prefix-matching problems
K-th elements, top-K, and scheduling problems
Grid traversals, islands, and 2D DP
Merge sort variants, binary search extensions, and D&C DP
Range queries, point updates, and Fenwick tree problems
Build confidence with well-structured easy problems
The real interview level — medium problems only
Elite-level problems that test your limits
All difficulty levels — the complete DSA workout
Questions tagged by top tech companies — Google, Amazon, Meta & more
Frequently asked Google interview questions
Top Amazon interview problems including leadership principle style