281. Cycle in an Undirected Graph
MediumUnion-FindDFS
Print YES if the undirected graph contains a cycle, else NO. There are no self-loops or repeated edges.
Input format
Line 1: n m Next m lines: u v
Output format
YES or NO
Example 1
Input
3 3 1 2 2 3 3 1
Output
YES
Example 2
Input
4 3 1 2 2 3 3 4
Output
NO
Constraints
1 ≤ n ≤ 10⁵
Read input from standard input and print the answer to standard output. Your code is judged against 4 test cases, most of them hidden.
Loading the MyLoginn IDE…