Course map

Every interview pattern as a territory. Explore every published problem and room free, with no account.

The Course map: Every interview pattern as a territory. Explore every published problem and room free, with no account.

  1. Arrays — Searching, two pointers, and array manipulation.
  2. Strings — Character arrays, parsing, and string algorithms.
  3. Hash Maps — Key–value lookups, counting, and frequency maps.
  4. Linked Lists — Rewiring nodes, fast & slow pointers, and list tricks.
  5. Stacks & Queues — LIFO/FIFO structures and monotonic patterns.
  6. Trees — Traversals, BSTs, and recursive tree walks.
  7. Tries — Prefix trees for autocomplete and word search.
  8. Heaps — Priority queues, heap operations, and top-K.
  9. Matrices — 2-D grids, traversal, and matrix manipulation.
  10. Database — SQL-style queries and relational patterns.
  11. Backtracking — Explore decision trees depth-first, undo dead ends.
  12. Graphs — Traverse, color, order, and search weighted graphs.
  13. Binary Search — Halve the search space on sorted data.
  14. Dynamic Programming — Tabulate overlapping subproblems for optimal answers.
  15. Greedy — Make locally optimal choices for global solutions.
  16. Sliding Window — Maintain a window over arrays and strings.
  17. Sorting — Comparison sorts, merge sort, quicksort, and heap sort.
  18. Intervals — Merge, insert, and schedule interval problems.
  19. Prefix Sum — Precompute cumulative sums for range queries.
  20. Math — Number theory, combinatorics, and arithmetic tricks.
  21. Streams & I/O — Merge streams, iterators, and sequential data.
  22. System Design — Design data structures and APIs for real-world systems.
  23. Go (Micro) — Master the tiny Go code shapes that combine into full algorithms and data-structure solutions.
  24. Java (Micro) — Master the small Java code shapes that combine into full algorithms and data-structure solutions.
  25. Python (Micro) — Master the small Python code shapes that combine into full algorithms and data-structure solutions.
  26. Algorithm Patterns — The reusable moves behind interview problems — recognize each pattern, run it, and prove why it works.