学步园

#include <cstdio>
#include <queue>
#include <vector>
#include <cstdlib>
#include <cstring>
using namespace std;
const int N=30010;
int n,m,e;
int v[N],ans[N];
vector<int> p[N];

void topSort()
{
    priority_queue<int> Q;
    int i,size,tmp;
    for(i=1;i<=n;i++)
        if( v[i]==0 ) Q.push(i);
    while( !Q.empty() ){
        tmp=Q.top(); Q.pop();
        size=p[tmp].size();
        for(i=0;i<size;i++){
            v[ p[tmp][i] ]--;
            if( v[p[tmp][i]]==0 ) Q.push( p[tmp][i] );
        }
        ans[e++]=tmp;
    }
}
int main()
{
    int i,t,x,y;
    scanf("%d",&t);
    while( t-- )
    {
        scanf("%d%d",&n,&m);
        for(i=1;i<=n;i++)
            p[i].clear();
        memset(ans,0,sizeof(ans));
        for(i=0;i<m;i++){
            scanf("%d%d",&x,&y);
            v[x]++;
            p[y].push_back(x);
        }
        e=0;
        topSort();
        for(i=n-1;i>0;i--)
            printf("%d ",ans[i]);
        printf("%d\n",ans[i]);
    }
    return 0;
}