UVA 10110

楼管大叔关N个灯走N趟，第i趟关可以被i整除的灯，

那么因子数目必须是奇数最后才能是亮的，否则N = i * k，第i趟打开第k趟关掉

#include <iostream>#include <sstream>#include <cstdio>#include <cstring>#include <cmath>#include <string>#include <vector>#include <set>#include <cctype>#include <algorithm>#include <cmath>#include <deque>#include <map>using namespace std;///#define INF 0xffffff7#define MAXN 200 ///int main(){///int i, j;unsigned long n, r;while(1){cin >> n;if (n == 0)break;r = floor(sqrt(n));if (r * r == n)cout << "yes" << endl;elsecout << "no" << endl;}    ///    return 0;}