A friend of mine had this question in recent G interview and I am not sure what\'d be the best approach. Say we have the following "directed" graph:\n\n<img src="https://assets.leetcode.com/users/images/181a3d79-82e0-4e17-856c-89c754007a6f_1619588789.2374604.png" alt="why" width="500"/>\n\n\nThe goal is to find the longest path we can have from "any" of nodes in the graph. For the above graph, the answer is `C` with length of `6`.\n\nI can solve this problem for a DAG but not sure how to solve this for a directed graph with cycle **in O(n) time**. Any idea?

A friend of mine had this question in recent G interview and I am not sure what\'d be the best approach. Say we have the following "directed" graph:\n\n\n\n\nTh