HDU 1285 确定比赛名次

拓扑排序模板题，判断 当前点出度与入度。

#include<cstdio>
#include<cstring>
#include<cstdlib>

struct N
{
    int data;
    int n;
    struct N *next;
}*head[510];

void init(int n)
{
    for(int i = 1;i <= n; i++)
    {
        head[i] = (struct N *)malloc(sizeof(struct N));
        head[i]->next = NULL;
        head[i]->n = 0;
        head[i]->data = -1;
    }
}

int link(int u,int v)
{
    struct N *p1,*p2;
    for(p1 = head[u],p2 = p1->next; p2 != NULL; p1 = p1->next,p2 = p2->next)
    {
        if(v == p2->data) return 0;
        if(p1->data < v && p2->data > v)
        {
            N *p = (struct N *)malloc(sizeof(struct N));
            p->data = v;
            p->next = p1->next;
            p1->next = p;
            return 1;
        }
    }
    N *p = (struct N *)malloc(sizeof(struct N));
    p->data = v;
    p->next = p1->next;
    p1->next = p;
    return 1;
}

void check(int i)
{
    for(N *p = head[i]->next;p != NULL;p = p->next)
    {
        head[p->data]->n--;
    }
}

int q[510],j,hash[510];

int main()
{
    int n,m,u,v,i;
    while(scanf("%d %d",&n,&m) != EOF)
    {
        init(n);
        memset(hash,0,sizeof(hash));
        for(i = 0;i < m; i++)
        {
            scanf("%d %d",&u,&v);
            if(link(u,v))
                head[v]->n++;
        }
        for(i = 1,j = 0;i <= n && j < n; i++)
        {
            if(head[i]->n == 0  && !hash[i])
            {
                check(i);
                hash[i] = 1;
                q[j++] = i;
                i = 0;
            }
        }
        printf("%d",q[0]);
        for(i = 1;i < j; i++)
            printf(" %d",q[i]);
        printf("\n");
    }
    return 0;
}