Graph Diameter by BFS

Problem

Compute the diameter of a connected undirected unweighted graph: the maximum shortest-path distance between any two nodes.

Run a BFS from every node and take the largest distance found. Return -1 when the graph is disconnected and 0 for a single node.

Hint

The longest BFS distance over all starting nodes is the diameter.

case 1

in: [5,[[0,1],[1,2],[2,3],[3,4]]]

expected: 4

case 2

in: [4,[[0,1],[0,2],[0,3]]]

expected: 2

case 3

in: [4,[[0,1],[2,3]]]

expected: -1

case 4

in: [1,[]]

expected: 0

case 5

in: [2,[[0,1]]]

expected: 1

Starter codePython

def graph_diameter(n, edges):
    # Your code here
    pass

5 test cases · run your code against them in the editor