[NeetCode 150] Redundant Connection

Redundant Connection

You are given a connected undirected graph with n nodes labeled from 1 to n. Initially, it contained no cycles and consisted of n-1 edges.

We have now added one additional edge to the graph. The edge has two different vertices chosen from 1 to n, and was not an edge that previously existed in the graph.

The graph is represented as an array edges of length n where edges[i] = [ai, bi] represents an edge between nodes ai and bi in the graph.

Return an edge that can be removed so that the graph is still a connected non-cyclical graph. If there are multiple answers, return the edge that appears last in the input edges.

Example 1:

Input: edges = [[1,2],[1,3],[3,4],[2,4]]

Output: [2,4]

Example 2:

Input: edges = [[1,2],[1,3],[1,4],[3,4],[4,5]]

Output: [3,4]