Watch 10 video solutions for Longest Cycle in a Graph, a hard level problem involving Depth-First Search, Graph, Topological Sort. This walkthrough by NeetCodeIO has 22,081 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
You are given a directed graph of n nodes numbered from 0 to n - 1, where each node has at most one outgoing edge.
The graph is represented with a given 0-indexed array edges of size n, indicating that there is a directed edge from node i to node edges[i]. If there is no outgoing edge from node i, then edges[i] == -1.
Return the length of the longest cycle in the graph. If no cycle exists, return -1.
A cycle is a path that starts and ends at the same node.
Example 1:
Input: edges = [3,3,4,2,3] Output: 3 Explanation: The longest cycle in the graph is the cycle: 2 -> 4 -> 3 -> 2. The length of this cycle is 3, so 3 is returned.
Example 2:
Input: edges = [2,-1,3,1] Output: -1 Explanation: There are no cycles in this graph.
Constraints:
n == edges.length2 <= n <= 105-1 <= edges[i] < nedges[i] != i