UESTC 898 方老师和缘分 --二分图匹配+强连通分量

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#define Mod 1000000007
using namespace std;
#define N 200007

std::vector<int> G[4005];
int low[4005],dfn[4005];
int instk[4005],bel[4005];
int n,Time,cnt,res;
stack<int> stk;
int ans[2005];


void Tarjan(int u)
{
    low[u] = dfn[u] = ++Time;
    stk.push(u);
    instk[u] = 1;
    for(int i=0;i<G[u].size();i++)
    {
        int v = G[u][i];
        if(!dfn[v])
        {
            Tarjan(v);
            low[u] = min(low[u],low[v]);
        }
        else if(instk[v])
            low[u] = min(low[u],dfn[v]);
    }
    if(low[u] == dfn[u])
    {
        cnt++;
        int v;
        do
        {
            v = stk.top();
            stk.pop();
            instk[v] = 0;
            bel[v] = cnt;
        }while(u != v);
    }
}

void init()
{
    memset(G,0,sizeof(G));
    memset(instk,0,sizeof(instk));
    memset(bel,-1,sizeof(bel));
    memset(low,0,sizeof(low));
    memset(dfn,0,sizeof(dfn));
    Time = cnt = 0;
    while(!stk.empty())
        stk.pop();
}

int main()
{
    int i,j,u,v,k;
    while(scanf("%d",&n)!=EOF)
    {
        init();
        for(i=1;i<=n;i++)
        {
            scanf("%d",&k);
            while(k--)
            {
                scanf("%d",&v);
                G[i].push_back(v+n);
            }
        }
        for(i=1;i<=n;i++)
        {
            scanf("%d",&v);
            G[v+n].push_back(i);
        }
        for(i=1;i<=n;i++)
        {
            if(!dfn[i])
                Tarjan(i);
        }
        for(u=1;u<=n;u++)
        {
            k = 0;
            for(i=0;i<G[u].size();i++)
            {
                v = G[u][i];
                if(bel[u] == bel[v])
                    ans[k++] = v-n;
            }
            sort(ans,ans+k);
            printf("%d",k);
            for(i=0;i<k;i++)
                printf(" %d",ans[i]);
            printf("\n");
        }
    }
    return 0;
}