hdu 1285 确定比赛名次

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int n,m,p1,p2;
int indegree[500010],match[505][505],flag;
void tuopu()
{
    int i,j,k,flag=0;
    for(j=1;j<=n;j++)
    for(i=1;i<=n;i++)
    {
        if(indegree[i]==0)
        {
            if(flag==0)
            printf("%d",i),flag++;
            else printf(" %d",i);
            indegree[i]=-1;
            for(k=0;k<=n;k++)
            {
                if(match[i][k]==1) indegree[k]--;
            }
            break;//一定要break掉
        }
    }
    printf("\n");
}
int main()
{
    int i,j,k;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        memset(match,0,sizeof(match));
        memset(indegree,0,sizeof(indegree));
        for(i=0;i<m;i++)
        {
            scanf("%d%d",&p1,&p2);
            if(match[p1][p2]==0)
            {
                indegree[p2]++;
                match[p1][p2]=1;
            }
        }
        tuopu();
    }
    return 0;
}