poj 1094 Sorting It All Out (拓扑排序）

效率太低了，反思~~~~

1:题意理解错误

where xxx is the number of relations processed at the time either a sorted sequence is determined or an inconsistency is found, whichever comes first, and yyy...y is the sorted, ascending sequence. 

明明没说是按它列的顺序求解--关系的数量，

2：对环的处理上没有搞好 

#include<stdio.h>
#include<string.h>
#define N 30
int map[N][N],sum[N],temp[N];
char alp[N];
int n,m;
int topology()
{
    int t=1,zero,k;
    memset(alp,'\0',sizeof(alp));
    memcpy(temp,sum,sizeof(temp));
    for(int i=0;i<n;i++)
    {
        zero=0;
        for(int j=0;j<n;j++)
        if(!temp[j])
        {
            zero++;k=j;
        }
        if(zero>1) t=-1;
        if(zero==0) return 0;
        temp[k]=-1,alp[i]='A'+k;
        for(int j=0;j<n;j++)
        {
            if(map[k][j])
            {
                temp[j]--;
            }
        }

    }
    return t;
}
int main()
{
    while(scanf("%d%d%*c",&n,&m),n+m)
    {
        memset(map,0,sizeof(map));
        memset(sum,0,sizeof(sum));
        int ok=0;
        for(int i=1;i<=m;i++)
        {
            char st[4];gets(st);
            if(!map[st[0]-'A'][st[2]-'A'])
            {
             map[st[0]-'A'][st[2]-'A']=1;
             sum[st[2]-'A']++;
            }

            if(ok) continue;
            int t=topology();
            if(t==1)
            {
                ok=1;
                printf("Sorted sequence determined after %d relations: %s.\n",i,alp);
            }
            else if(!t)
           {
             ok=1;
             printf("Inconsistency found after %d relations.\n",i);
           }
        }
       if(!ok)
       printf("Sorted sequence cannot be determined.\n");

    }
    //system("pause");
}