HDU - 1285 确定比赛名次

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int MAXN = 600;

int G[MAXN][MAXN],in[MAXN],ans[MAXN];
int n,m;

void topsort(){
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (G[i][j])
                in[j]++;
    for (int i = 1; i <= n; i++){
        int k = 1; 
        while (in[k] != 0)
            k++;
        ans[i] = k;
        in[k]--;
        for (int j = 1; j <= n; j++)
            if (G[k][j])
                in[j]--;
    }
}

int main(){
    while (scanf("%d%d",&n,&m) != EOF){
        memset(in,0,sizeof(in));
        memset(ans,0,sizeof(ans));
        memset(G,0,sizeof(G));
        for (int i = 0; i < m; i++){
            int a,b;
            scanf("%d%d",&a,&b);
            G[a][b] = 1;
        }
        topsort();
        for (int i = 1; i < n; i++)
            printf("%d ",ans[i]);
        printf("%d\n",ans
); 
    }            
    return 0;
}