poj 1730 Perfect Pth Powers

Perfect Pth PowersTime Limit: 1000MS Memory Limit: 10000K
Total Submissions: 15918 Accepted: 3605


Description
We say that x is a perfect square if, for some integer b, x = b2. Similarly, x is a perfect cube if, for some integer b, x = b3. More generally, x is a perfect pth power if, for some integer b, x = bp. Given an integer x you are to determine the largest p such that x is a perfect pth power.

Input
Each test case is given by a line of input containing x. The value of x will have magnitude at least 2 and be within the range of a (32-bit) int in C, C++, and Java. A line containing 0 follows the last test case.

Output
For each test case, output a line giving the largest integer p such that x is a perfect pth power.

Sample Input
17
1073741824
25
0

Sample Output
1
30
2

Source
Waterloo local 2004.01.31

//184K    32MS    C++    694B    
//我会告诉你我WA了很多次吗- -
//直接暴力的思想，时间复杂度为O(sqrt(n)) 
#include<stdio.h>
#include<math.h>
__int64 _abs(__int64 a)
{
    return a>0?a:-a;
}
int main(void)
{
    __int64 n;
    while(scanf("%I64d",&n),n)
    {
        __int64 i,flag;
        __int64 ans;
        if(n<0) flag=-1;
        else flag=1;
        __int64 m=(__int64)sqrt(_abs(n)*1.0);
        for(i=2;i<=m;i++){
            ans=1;
            __int64 temp=i*flag;
            while(_abs(temp)<_abs(n)){ //每一个数都试一次 
                temp*=(i*flag);
                ans++;
            }
            if(temp==n) break;//符合条件跳出循环 
            else ans=1;
        }
        printf("%d\n",ans);
    }
    return 0;
}