strongly connected component

void toposort(int u){
    ara[u] = 1;
    for(int i=0;i<graph[u].size();i++){
        if(ara[graph[u][i]]==0) toposort(graph[u][i]);
    }
    ara[u] = 2;
    stk.push(u);
}

void dfs(int u, int ans){
    ara2[u] = 1;
    for(int i=0;i<rgraph[u].size();i++){
        if(ara2[rgraph[u][i]]==0) dfs(rgraph[u][i], ans);
    }
    ara2[u] = ans;
}

int stronglyconnected(int n){
    memset(ara, 0, sizeof ara);
    memset(ara2, 0, sizeof ara2);
    for(int i=1;i<=n;i++) if(!ara[i]) toposort(i);
    int ans = 0;
    while(!stk.empty()){
        if(ara2[stk.top()]==0){
            ans++;
            dfs(stk.top(), ans);
        }
        stk.pop();
    }
    return ans;
}