HDU 1285 确定比赛名次。

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=1285

纯粹的拓扑排序

#include <stdio.h>
#include <string.h>
int count,n,in[505],map[505][505],vis[505],sort[505];

void topo(int x)
{
    vis[x] = 1;
    sort[count] = x;
    count++;
    int i;
    for(i = 1;i <= n;i++)
    {
        if(map[x][i] && !vis[i])//只对未访问过的临界点有效~
        in[i]--;
    }
}

int main()
{
    int a,b,m,i,j;
    while(~scanf("%d %d",&n,&m))
    {
        memset(map,0,sizeof(map));
        memset(in,0,sizeof(in));
        memset(vis,0,sizeof(vis));
        for(i = 0;i < m;i++)
        {
            scanf("%d %d",&a,&b);
            if(map[a][b] == 0)
            map[a][b] = 1,in[b]++;
        }
        count = 0;
        while(count < n)
        {
            for(i = 1;i <= n;i++)
            {
                if(!vis[i] && !in[i])//没有访问过且in为零
                {
                    topo(i);
                    break;
                }
            }
        }
        for(i = 0;i < n-1;i++)
        printf("%d ",sort[i]);
        printf("%d\n",sort[i]);
    }
}