BUG : bridge finding algorithm offline

[SubhramRanaRZP]

Article: Finding Bridges in O(N+M)

Problem:
If there is double edge between two nodes, due to if (to == p) continue;, the edge (v-to) will be considered as a bridge, which is not correct.
Here is the modified code.

1. introduce a new variable called parentSkipped inside the dfs()
   bool parentSkipped = false;
2. instead of just if (to == p) continue; do the following
   if (to == p && !parentSkipped) {
   parentSkipped = true;
   continue;
   }

[adamant-pwn]

Hi, thanks for bringing that up! Would you like to make a pull request with this change?