Motivation
Lesson 2 of 9 in Coddy's Breadth-First Search - Graph Algorithms course.
BFS uses a queue (first in, first out) so that vertices are processed in the exact order they are discovered, which produces the layer-by-layer exploration.
Why learn BFS?
- Shortest paths: in an unweighted graph, BFS finds the fewest-edges path from the start to every other vertex.
- Simple and linear: it runs in O(V + E) with a queue and a visited marker.
- Everywhere: shortest hops in networks, word ladders, maze solving, and level-order tree traversal are all BFS.
As with DFS, we enqueue a vertex's neighbors in ascending order so results are predictable.
Try it yourself
This lesson doesn't include a code challenge.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
