Breadth-First Search (BFS)

overview

Summary

Breadth-first search (BFS) is a method of exploring a graph outward layer-by-layer from a starting point. Its core purpose is to measure distance in terms of edge-steps, making it ideal for finding the shortest path in unweighted graphs. BFS visits every node exactly once and every edge at most once, giving it a time complexity of O(V+E). It is used in problems where we care about how many moves, hops, or links it takes to reach something - such as routing in networks, social-distance analysis, puzzle solving, and connectivity detection. BFS is reliable, systematic, and guarantees the shallowest-level discovery of nodes, making it an essential tool in both theoretical graph theory and real-world computing applications.