Edges Whose Removal Disconnects a Network

### Problem The connected undirected graph has n labeled servers 0 through n-1, with no self-loops or repeated connections. Return every edge whose removal makes some pair of servers unable to reach each other. Edges and their endpoint orientations may be returned in any order. ```cpp class Solution { public: vector<vector<int>> criticalConnections(int n, vector<vector<int>>& connections); }; ``` ### Examples **Example 1:** ```text Input: n = 3, connections = [[0,1],[1,2]] Output: [[0,1],[1,2]] Explanation: Removing either edge separates an endpoint from another server. ``` **Example 2:** ```text Input: n = 4, connections = [[0,1],[1,2],[2,3],[3,0]] Output: [] Explanation: Every removed edge has an alternate route around the remaining cycle. ``` ### Constraints - `2 <= n <= 100000`. - The connected graph has between n-1 and 100000 edges. - Each edge joins two distinct labels in `[0,n-1]`. - There are no repeated undirected edges. ### Contract considerations The output is a set of undirected critical edges; a fixed edge order is not required. ```hint Read the boundary condition Must a reported undirected edge keep the same endpoint orientation and list position as in the input? ``` ### What a Strong Answer Covers The output is a set of undirected critical edges; a fixed edge order is not required. ### Follow-up Questions Optional practice extension, separate from the original task: How would the algorithm change if parallel connections were allowed?