确定比赛名次(最基本的拓扑排序)

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <cmath>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define LL long long
#define INF 0x3f3f3f3f
using namespace std;
const int MX=1e3+100;
int deg[MX],Map[MX][MX];
int main()
{
    int n,m;
    while (~scanf ("%d %d",&n,&m)){
        memset(deg,0,sizeof(deg));
        memset(Map,0,sizeof (Map));
        for (int i=0;i<m;i++){
            int u,v;
            scanf ("%d %d",&u,&v);
            if (!Map[u][v]){
                Map[u][v]=1;
                deg[v]++;
            }
        }
        for (int i=1;i<=n;i++){                 //拓扑排序
            for (int j=1;j<=n;j++){
                if (!deg[j]){
                    deg[j]--;
                    if (i!=n) printf ("%d ",j); //因为是从1到n，所以输出的一定是按照字典序输出的
                    else printf ("%d\n",j);
                    for (int k=1;k<=n;k++){
                        if (Map[j][k]){
                            deg[k]--;
                        }
                    }
                    break;
                }
            }
        }
    }
    return 0;
}