ORIGINAL CODING QUESTION
Undirected loop check
Print 1 if the undirected multigraph contains a cycle, otherwise 0. A self-loop is a cycle; two parallel edges form a cycle.
Original exercise · medium. Editorial role relevance does not imply a company has asked this question.
Input and output
n m, then m vertex pairs (u,v). Vertices are zero-based.
Constraints
1 ≤ n ≤ 30; 0 ≤ m ≤ 100; vertex IDs in [0,n).
Example 1
Input
3 3 0 1 1 2 2 0
Output
1
The triangle closes a cycle.
Example 2
Input
3 2 0 1 1 2
Output
0
A simple path has no cycle.
Explain your approach
Explain your time and auxiliary space complexity. Which input makes your algorithm work hardest?
Private grading inputs, expected outputs and canonical reference implementations are withheld. Authored expected outputs were cross-checked with independent reference oracles; compiler/runtime behavior still needs a verified execution provider.
Hint 1
An edge joining already-connected endpoints closes a cycle.
Hint 2
Union endpoints otherwise.
Hint 3
Self-loops and parallel edges need explicit semantics.
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