HDU 4324 Triangle LOVE(拓扑排序）

#include <stdio.h>
#include <string.h>
char str[2001][2001];
int o1[2001],o2[2001],k[2001];
int main()
{
int t,i,j,num = 0,n,z,nu;
scanf("%d",&t);
while(t--)
{
num ++;
memset(k,0,sizeof(k));
memset(o1,0,sizeof(o1));
memset(o2,0,sizeof(o2));
scanf("%d%*c",&n);
for(i = 0; i <= n-1; i ++)
gets(str[i]);
for(i = 0; i <= n-1; i ++)
{
for(j = 0; j <= n-1; j ++)
{
if(str[i][j] == '1')
{
o1[i] ++;
o2[j] ++;
}
}
}
nu = 0;
for(;;)
{
z = 0;
for(i = 0; i <= n-1; i ++)
{
if(o2[i] == 0&&!k[i])
{
k[i] = 1;
z = 1;
nu ++;
for(j = 0;j <= n-1;j ++)
{
if(str[i][j] == '1'&&!k[j])
{
o2[j] --;
}
}
}
}
if(nu == n) break;
if(!z) break;
}
if(nu == n)
z = 0;
else
z = 1;
printf("Case #%d: ",num);
if(z)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}