hdu 1285 确定比赛名次

#include <algorithm>
#include <cstring>
#include <cstdio>
#include <queue>
#define N 505
using namespace std;
priority_queue<int,vector<int>,greater<int> >q;
struct Edge{
    int next,to;
}edge[N*N];
int ans[N],r=0,head[N],cnt,rd[N],n,m;
void tppx()
{
    for(int i=1;i<=n;++i) if(!rd[i]) q.push(i) ;
    for(int now;!q.empty();)
    {
        now=q.top();q.pop();
        ans[++r]=now;
        for(int i=head[now];i;i=edge[i].next)
        {
            int v=edge[i].to;
            if(rd[v])
            {
                rd[v]--;
                if(!rd[v]) q.push(v) ; 
            }
        }
    }
}
inline void ins(int u,int v)
{
    edge[++cnt].next=head[u];
    edge[cnt].to=v;
    head[u]=cnt;
}
int main()
{
    for(;scanf("%d%d",&n,&m)!=EOF;)
    {
        memset(edge,0,sizeof(edge));
        memset(head,0,sizeof(head));
        memset(rd,0,sizeof(rd));
        r=cnt=0;
        for(int a,b;m--;)
        {
            scanf("%d%d",&a,&b);
            ins(a,b);
            rd[b]++;
        }
        tppx();
        for(int i=1;i<r;++i) printf("%d ",ans[i]);
        printf("%d\n",ans[r]);
    }
    return 0;
}