拓扑排序

#include<iostream>
#include<cstdio>
#include<string.h>
#include<cstring>
#include<string>
#include<stack>
#include<set>
#include<algorithm>
#include<cmath>
#include<vector>
#include<map>

#define LOCAL
#define ll long long
#define lll unsigned long long
#define MAX 1000009
#define eps 1e-8
#define INF 0x7fffffff
#define mod 1000000007

using namespace std;
/*

题意：

想法：

*/
int n,m;
int head[MAX];
int p[MAX];
int next[MAX];
int edgecnt;
int Count[MAX];

void addedge(int u,int v)
{
    ++edgecnt;
    p[edgecnt] = v;
    next[edgecnt] = head[u];
    head[u] = edgecnt;
}
void init()
{
    memset(Count,0,sizeof(Count));
    memset(head,0,sizeof(head));
    memset(next,0,sizeof(next));
}
int topsort()
{
    int sum = 0;
    stack<int>Q;
    int top =  -1;
    for(int i = 1; i<=n; i++)
    {
        if(Count[i]==0)
        {
            Q.push(i);
        }
    }
    if(Q.empty())
    {
        return 1;
    }
    else
    {
        while(!Q.empty())
        {
            int u = Q.top();
            Q.pop();
            sum++;
            for(int i = head[u]; i; i = next[i])
            {
                int v = p[i];
                Count[v]--;
                if(Count[v]==0)
                {
                    Q.push(v);
                }
            }
        }
    }
    //cout<<sum<<endl;
    if(sum<n)
        return 1;
    else
        return 0;
}
int main()
{
    //freopen("date.in","r",stdin);
    int T;
    scanf("%d",&T);
    while(T--)
    {
        init();
        scanf("%d%d",&n,&m);
        for(int i = 0; i<m; i++)
        {
            int u,v;
            scanf("%d%d",&u,&v);
            Count[v]++;
            addedge(u,v);
        }
        bool ans = topsort();
        if(ans)
            puts("Wrong");
        else
            puts("Correct");
    }
    return 0;
}