Visualized DSA Strategies

Episode 0 The Visual Dictionary

9 min · JavaScript

Episode 0The Visual Dictionary

▶ This video is coming to YouTube soon.

Before we solve a single interview problem, we agree on a language. Every data structure in this course has one shape and one colour: arrays, strings, counters, matrices, hash maps, hash sets, stacks, queues, linked lists and heaps. For each one you'll see what the shape means, how to declare it in JavaScript, and what its operations cost.

What you'll learn

  • How to read pointers, windows and the four highlight colours
  • Arrays, strings, new Array(26).fill(0) counters and 2D arrays built with Array.from, and why indexing is O(1)
  • Map vs Set: key → value vs membership only, and why a Map beats a plain object
  • Stacks, queues and deques: an array as a stack, a head index for a queue, and which end you can touch
  • Linked lists and heaps (JavaScript has no built-in heap: a small one by hand), and what makes them different

Chapters

  1. 0:00Intro
  2. 0:18How to read the pictures
  3. 1:02Variable
  4. 1:36Array
  5. 2:12String
  6. 2:57Counter: new Array(26).fill(0)
  7. 3:44Matrix: an array of arrays
  8. 4:28Hash map: Map
  9. 5:12Hash set: Set
  10. 5:53Stack: an array
  11. 6:29Queue and deque: an array and a head index
  12. 7:18Linked list
  13. 7:52Heap (written by hand)
  14. 8:41The whole dictionary