#Breadth-First Search Algorithm Breadth-First Search (BFS) is a graph traversal algorithm that explores all the vertices of a graph or tree in breadthward motion. It starts at a designated node (often called the "root" in a tree or the "source" in a graph) and explores all of its neighbors at the current level before moving on to the next level of neighbors. BFS is typically used to search for a specific node or to find the shortest path between two nodes in an unweighted graph.