public class Solution
extends Object
1192 - Critical Connections in a Network\.
Hard
There are `n` servers numbered from `0` to `n - 1` connected by undirected server-to-server `connections` forming a network where connections[i] = [ai, bi] represents a connection between servers ai and bi. Any server can reach other servers directly or indirectly through the network.
A _critical connection_ is a connection that, if removed, will make some servers unable to reach some other server.
Return all critical connections in the network in any order.
**Example 1:**
**Input:** n = 4, connections = \[\[0,1],[1,2],[2,0],[1,3]]
**Output:** [[1,3]]
**Explanation:** [[3,1]] is also accepted.
**Example 2:**
**Input:** n = 2, connections = \[\[0,1]]
**Output:** [[0,1]]
**Constraints:**
* 2 <= n <= 105
* n - 1 <= connections.length <= 105
* 0 <= ai, bi <= n - 1
* ai != bi
* There are no repeated connections.