Redundant Connection
Difficulty: Medium
Category: DSA
Topics: Depth-First Search, Breadth-First Search, Union Find, Graph
Asked at: Amazon
In this problem, a tree is an **undirected graph** that is connected and has no cycles.
You are given a graph that started as a tree with `n` nodes labeled from `1` to `n`, with one additional edge added. The added edge has two **different** vertices chosen from `1` to `n`, and was not an edge that already existed. The graph is represented as an array `edges` of length `n` where `edges[i] = [ai, bi]` indicates that there is an edge between nodes `ai` and `bi` in the graph.
Return _an edge that can be removed so that the resulting graph is a tree of _`n`_ nodes_. If there are multiple answers, return the answer that occurs last in the input.
**Example 1:**
**Input:** edges = [[1,2],[1,3],[2,3]]
**Output:** [2,3]
```
**Example 2:**
**Input:** edges = [[1,2],[2,3],[3,4],[1,4],[1,5]]
**Output:** [1,4]
```
**Constraints:**
- `n == edges.length`
- `3 <= n <= 1000`
- `edges[i].length == 2`
- `1 <= ai < bi <= edges.length`
- `ai != bi`
- There are no repeated edges.
- The given graph is connected.