Practice
Watching an algorithm is the start. These are the places on the site that make you do it yourself, and count a topic as done when you can.
Coding challenges
Write the solution in the browser and run it against test cases. Passing completes the topic. 17 topics have one.
- Stack Data StructureBeginnerCode15m
- Binary SearchBeginnerCode15m
- Depth-First Search (DFS)IntermediateCode20m
- Topological SortIntermediateCode25m
- Hash Map: Collision HandlingIntermediateCode20m
- Trie (Prefix Tree)IntermediateCode20m
- Union-Find (Disjoint Set)IntermediateCode20m
- LRU Cache DesignIntermediateCode25m
- Backtracking (N-Queens)AdvancedCode30m
- Two Pointers TechniqueBeginnerCode20m
- Sliding WindowIntermediateCode25m
- Monotonic StackIntermediateCode25m
- Prefix SumBeginnerCode15m
- Advanced Binary Search PatternsAdvancedCode30m
- Bit ManipulationIntermediateCode15m
- Greedy AlgorithmsIntermediateCode20m
- Interval SchedulingIntermediateCode20m
Interview patterns
The patterns most coding interview questions reduce to, with the signals that a problem needs each one and interview questions to try.
Coding interview patternsQuizzes and hands-on activities
Every topic ends with a quiz and a hands-on activity: put the steps in order, fill in the architecture, or sort the concepts. A perfect quiz or a solved activity completes the topic.
System design drills
Learn the interview method, then work through full designs: requirements, estimates, API, data model and trade-offs. The study guides and canvas need a desktop-width screen.