Relatives
| Time Limit: 1000MS | Memory Limit: 65536K | |
| Total Submissions: 9411 | Accepted: 4453 |
Description
Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if there are no integers x > 1, y > 0, z > 0 such that a = xy and b = xz.
Input
There are several test cases. For each test case, standard input contains a line with n <= 1,000,000,000. A line containing 0 follows the last case.
Output
For each test case there should be single line of output answering the question posed above.
Sample Input
7 12 0
Sample Output
6 4
Source
MYCode:
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
int euler(int x)
{
int res=x;
int i;
for(i=2;i*i<=x;i++)
{
if(x%i==0)
{
res=res*1.0/i*(i-1);
while(x%i==0)x/=i;
}
}
if(x>1)res=res/x*(x-1);
return res;
}
int main()
{
int p;
while(scanf("%d",&p))
{
if(p==0)
break;
int ans=euler(p);
printf("%d\n",ans);
}
}
//
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
int euler(int x)
{
int res=x;
int i;
for(i=2;i*i<=x;i++)
{
if(x%i==0)
{
res=res*1.0/i*(i-1);
while(x%i==0)x/=i;
}
}
if(x>1)res=res/x*(x-1);
return res;
}
int main()
{
int p;
while(scanf("%d",&p))
{
if(p==0)
break;
int ans=euler(p);
printf("%d\n",ans);
}
}
//
欧拉函数模板题,可以使用素数表优化.