n皇后问题

 
int n;
int tot;
int C[20];
int result[20];
 
void (int cur)
{
    if(cur == n)
        tot++;
    else
        for(int i = 0; i <n; ++i)
        {
            int ok = 1;
            C[cur] = i;
            for(int j = 0; j < cur; ++j)
                if(C[cur] == C[j] || cur-C[cur] == j-C[j] || cur+C[cur] == j+C[j])
                {
                    ok = 0;
                    break;
                }
            if(ok)
                search(cur+1);
        }
}
 
int main()
{
    for(int i = 1; i <= 11 ; ++i)
    {
        n = i;
        tot = 0;
        search(0);
        result[i] = tot;
    }
    while(scanf("%d",&n) && n != 0)
        printf("%dn",result[n]);
    return 0;
}