Find if Path Exists in Graph

Graphs · BFS · Explore a frontier until you reach the goal · Easy · about 20 min

Why it matters

This is the cleanest bridge from trees to general graphs.

How it connects

Flood fill explored a grid. This uses the same visit rule on an adjacency list.

Try first

First write down what a node’s neighbours look like after you build an adjacency list.

Interview cue

Visited nodes prevent cycles from repeating work; traversal is O(V + E).