Crack the Coding Interview
For the algorithms half of the loop.
Follow the DSA roadmap, play the patterns as interactive games, then prove you can implement them by solving the matching challenges in your browser.
- Recognize the core DSA patterns under interview questions
- Trace graph, search and sort algorithms with confidence
- Implement and test solutions under time pressure
Data Structures & Algorithms Roadmap
The map: what to learn and in what order.
Fizz Buzz
A warm-up to get the engine under your fingers.
Binary Search: The Vault
The most-tested pattern, played.
Two Sum
Hash-map thinking, solved in your browser.
BFS: The Flood
Breadth-first search on a grid.
Build Order: DFS & Topological Sort
DFS, cycles and build order.
Six Degrees: Union-Find
Connectivity in near-constant time.
Dijkstra: The Last Mile
Weighted shortest paths.
Quicksort: The Pivot Pit
Partitioning and the worst case.
Merge Sort: The Cascade
The O(n log n) guarantee.
Valid Parentheses
The canonical stack problem.
Practising the patterns, not memorising
Coding interviews sample a handful of recurring patterns — arrays and hashing, two pointers, stacks, graphs, dynamic programming — under time pressure. This path builds intuition for them the way that actually sticks: playable algorithm games where you drive the problem and lose on instinct, then runnable challenges where you implement the fix with hidden tests.
The goal is recognition speed: seeing a new problem and knowing which pattern it wants, then writing it cleanly. That transfers well beyond interviews — it's the same instinct that makes real algorithmic work fast.