Shortest Path Between A and B

Prereq: BFS on Graph

Given an (unweighted) connected graph, return the length of the shortest path between two nodes A and B, in terms of the number of edges.

Assume there always exists a path between nodes A and B.

Input:

1graph = [[1, 2], [0, 2, 3], [0, 1], [1]]
2A = 0
3B = 3

Output: 2

Note that the graph is given as a 2-d list, where graph[i] is the list of nodes that node i is adjacent to. You can use the BFS template from BFS on Graphs as your starter code.

Try it yourself

Explanation