1022 舞会2

vijos

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
#include<queue>
using namespace std;
vector <int> a[202];
int n,m,dfs_num=0,dfn[202],low[202],color_num=0,color[202],st[202];
bool vis[202];
int top=0;
void Tarjan(int x)
{
    dfn[x]=++dfs_num;
    low[x]=dfs_num;
    vis[x]=true;
    st[++top]=x;

    for(int i=0;i<a[x].size();i++)
    {
        int k=a[x][i];
        if(!dfn[k])
        {
            Tarjan(k);
            low[x]=min(low[x],low[k]);
        }
        else if(vis[k]) low[x]=min(dfn[k],low[x]);//or     min=min(low[k],low[x]);
    }

    if(low[x]==dfn[x])
    {
        vis[x]=false;
        color[x]=++color_num;
        while(st[top]!=x)
        {
            vis[st[top]]=false;
            color[st[top]]=color_num;
            top--;
        }

        top--;
    }
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        int x;
        while(1){
            scanf("%d",&x);
            if(x==0) break;
            a[i].push_back(x);
        }

    }
    for(int i=1;i<=n;i++)
    {
        if(!dfn[i])
          Tarjan(i);
    }
    printf("%d
",color_num);
    return 0;
}