Biconnected Component

/*
 * Algorithm: Finding Biconnected Component
 * Complexity: O( V+E )
 * Note : Can be used for articulation/ bridge finding by using isArt etc
 */

long N; vector<long> edge[MAX+7];
bool vi[MAX+7],isArt[MAX+7];
long low[MAX+7],ind[MAX+7],I;// I for ind countin
long par[MAX+7],nChild[MAX+7];
stack< pair<long,long> > stk;
void Dfs( long u ){
    vi[u] = true; ind[u] = ++I; low[u] = I;
    nChild[u] = 0; isArt[u] = false;
    long i;
    for( i=0;i<edge[u].size();i++){
        long v = edge[u][i];
        if( !vi[v]){
            par[v] = u; nChild[u]++; stk.push( MP( u,v ) ); Dfs( v);
            if( low[v] >= ind[u] ){ // Find new Component
                while( stk.top() != MP(u,v) ) stk.pop(); // stk.top() is an edge
                stk.pop();
            }
            low[u] = min( low[u],low[v]);
        } else if( par[u] != v ){
            if( ind[v]<ind[u] ) stk.push( MP( u,v ) );
            low[u] = min( low[u],ind[v]);
        }
    }
}