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Charles Walsworth
All experiments
Experiment

Watching A* and Dijkstra Disagree (Sample)

A small visualiser built to see where a heuristic actually changes the search, rather than reading that it does.

  • TypeScript
  • Algorithms
  • Canvas

Sample content. This entry is placeholder material included to demonstrate the layout, not a record of real work.

The question

Everyone says A* explores fewer nodes than Dijkstra. On what kind of map, and by how much?

Approach

Draw both searches on the same grid, step for step, and count expanded nodes. Then break the heuristic on purpose and watch what happens.

ts
type Node = { x: number; y: number };
 
const manhattan = (a: Node, b: Node): number =>
  Math.abs(a.x - b.x) + Math.abs(a.y - b.y);

What I expect

That the advantage collapses on maps with lots of walls, because the heuristic keeps pointing the search into dead ends. Seeing that happen frame by frame is the whole point of building the visualiser instead of reading about it.