Breadth-First Search (BFS)

Breadth-first search produces breadth-first tree.
Path from s to x in BF tree is the shortest path in terms of the number of edges.

BFS: Given graph G = (V,E) and source s

• Visit every vertex reachable from s in one edge that has not already been visited
• Visit every vertex reachable from s in two edges that has not already been visited
• ...