#include<iostream>
using namespace std;
int bridge[N][2];
int col[N],low[N],dep[N],iscut[N],nb;
int dfs(int u,int fa,int depth)
{
    col[u]=1;
    dep[u]=low[u]=depth;
    int tol=0;
    int tofa=0;//判斷u,v之間是否有兩條以上邊
    int i,v;
    for(i=0;i<list[u].size();i++)
    {
        v=list[u][i];
        if(col[v]==0)
        {
            tol++;
            dfs(v,u,depth+1);
            low[u]=min(low[u],low[v]);
            /*求割點
            if(u==root&&col>1||x!=root&&low[v]>=dep[u])
                  iscut[u]=1;
            */
            /*求橋
            if(low[v]>dep[u])
            {
                bridge[++nb][0]=u;
                bridge[nb][1]=v;
            }
            */
        }
        else
        {
            if(v!=fa||tofa)
                low[u]=min(low[u],dep[v]);
            else
                tofa=1;
        }
    }
    return 0;
}
int main()
{
    
    root=1;
    dfs(root,-1,1);
    
}