Critical Connections - Input Example

Input: $n = 4$, connections = $[[0,1],[1,2],[2,0],[1,3]]$. This represents graph: $0-1$, $1-2$, $2-0$, $1-3$. The first three edges form a cycle $0-1-2-0$. No edges in this cycle are critical because you can reach any vertex through alternate paths.

Edge $1-3$ connects to a leaf vertex $3$ with no alternate path. It is the only critical connection. If you remove $1-3$, vertex $3$ becomes isolated from the rest of the network.