zju2723

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Semi-Prime

http://acm.zju.edu.cn/show_problem.php?pid=2723

Time limit: 1 Seconds

Memory limit: 32768K

Prime Number Definition: An integer greater than one is called a prime number if its only positive divisors (factors) are one and itself. For instance, 2, 11, 67, 89 are prime numbers but 8, 20, 27 are not.

Semi-Prime Number Definition: An integer greater than one is called a semi-prime number if it can be decompounded to TWO prime numbers. For example, 6 is a semi-prime number but 12 is not.

Your task is just to determinate whether a given number is a semi-prime number.

Input

There are several test cases in the input. Each case contains a single integer N (2 <= N <= 1,000,000)

Output

One line with a single integer for each case. If the number is a semi-prime number, then output “Yes”, otherwise “No”.

Sample Input

3
4
6
12

Sample Output

No
Yes
Yes
No

Author: LIU, Yaoting

Problem Source: Zhejiang University Local Contest 2006, Preliminary

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参考程序

#include <iostream>
#include <cmath>
using namespace std;
bool semiprime(int n)
{
     int N=sqrt(float(n));
     int k=0;
     for(int i=2;i<=N;i++)
     {
             if(n%i==0) k++;
     }
     if(k==1) return true;
     else return false;

 }
int main()
{
    int n;

    while(cin>>n)
    {
        if(semiprime(n))
            cout<<"Yes\n";
        else
            cout<<"No\n";
    }
}