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DSA learning path

Stacks & Queues

LIFO/FIFO, monotonic stacks and deque patterns.

Start with Valid Brackets

Problems in this path

  1. Valid Brackets
    Easy · Stack
    Open
  2. Evaluate Reverse Polish Notation
    Medium · Stack
    Open
  3. Next Greater Element
    Medium · Monotonic Stack
    Open
  4. Sliding Window Maximum
    Hard · Monotonic Deque
    Open
  5. Days Until a Warmer Temperature
    Medium · Monotonic Stack
    Open
  6. Simplify a Unix Path
    Medium · Stack Normalisation
    Open
  7. Decode a Bracketed String
    Medium · Nested Stack Frames
    Open
  8. Largest Histogram Rectangle
    Hard · Monotonic Increasing Stack
    Open
  9. Resolve Asteroid Collisions
    Medium · Collision Stack
    Open
  10. Simulate a Queue with Two Stacks
    Easy · Amortised Two Stacks
    Open

Read first

Stacks

Last in, first out. How a stack works, how to build one on top of an array, and the problems it solves, from matching brackets to undo.

11 min read

Queues and Deques

First in, first out. How a queue works, why a circular buffer makes both ends O(1), and where queues show up, from schedulers to breadth-first search.

13 min read