C++-POJ1094-Sorting It All Out[拓扑排序][邻接矩阵]

#include<cstdio>
#include<cstring>
int map[27][27],indegree[27],q[27];
int TopoSort(int n){
    int t=0,temp[27],p,m,flag=1;  //flag=1:有序 flag=-1:不确定
    for(int i=1;i<=n;i++)temp[i]=indegree[i];
    for(int i=1;i<=n;i++){
        m=0;for(int j=1;j<=n;j++)if(temp[j]==0)m++,p=j;//查找入度为零的顶点个数
        if(m==0)return 0; //有环
        if(m>1) flag=-1;  //无序
        q[++t]=p,temp[p]=-1;//入度为零的点入队
        for(int j=1;j<=n;j++)if(map[p][j]==1)temp[j]--;
    }
    return flag;
}
int main(){
    int n,m,sign,x,y;
    for(char s[5];scanf("%d%d",&n,&m)!=EOF;){
        if(n==0&&m==0)break;
        memset(map,0,sizeof(map)),sign=0;
        memset(indegree,0,sizeof(indegree));
        for(int i=1;i<=m;i++){
            scanf("%s",s);
            if(sign)continue;
            x=s[0]-'A'+1,y=s[2]-'A'+1;
            map[x][y]=1,indegree[y]++;
            int f=TopoSort(n);
            if(f==0)sign=1,printf("Inconsistency found after %d relations.
",i);
            if(f==1){
                sign=1,printf("Sorted sequence determined after %d relations: ",i);
                for(int j=1;j<=n;j++)printf("%c",q[j]+'A'-1);
                puts(".");
            }
        }
        if(!sign)puts("Sorted sequence cannot be determined.");
    }
    return 0;
}