uva 10110 - Light, more light

Light, more light

The Problem

There is man named "mabu" for switching on-off light in our University. He switches on-off the lights in a corridor. Every bulb has its own toggle switch. That is, if it is pressed then the bulb turns on. Another press will turn it off. To save power consumption (or may be he is mad or something else) he does a peculiar thing. If in a corridor there is `n' bulbs, he walks along the corridor back and forth `n' times and in i'th walk he toggles only the switches whose serial is divisable by i. He does not press any switch when coming back to his initial position. A i'th walk is defined as going down the corridor (while doing the peculiar thing) and coming back again.

Now you have to determine what is the final condition of the last bulb. Is it on or off?
 

The Input

The input will be an integer indicating the n'th bulb in a corridor. Which is less then or equals 2^32-1. A zero indicates the end of input. You should not process this input.

The Output

Output " yes" if the light is on otherwise " no" , in a single line.

Sample Input

3
6241
8191
0

Sample Output

no
yes
no

杭电上做过的题英文叙述改了下尽然不认识了......

Problem Description

There are many lamps in a line. All of them are off at first. A series of operations are carried out on these lamps. On the i-th operation, the lamps whose numbers are the multiple of i change the condition ( on to off and off to on ).

最后一个灯被操作几次就是他的因子个数，c=a*b；a=b时才会出现奇数次的操作所以只有完全平方数满足。

#include <stdio.h>

#include <math.h>
int main()
{long long n,num;
 while (scanf("%lld",&n),n)
 {num=sqrt(n);
  if (num*num==n) printf("yes\n");
             else printf("no\n"); 
 }
 return 0;
}