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.
素数定义
如果一个大于1的整数只有一个正整数(因子)是一个整数,那么它就称为素数。 例如,2,11,67,89是素数,但8,20,27不是。
半素数定义
如果一个大于1的整数可以分解为两个素数,则称其为一个半素数。 例如,6是一个半素数,但12不是。
你的任务只是确定一个给定的数字是否是一个半素数。
InputThere are several test cases in the input. Each case contains a single integer N (2 <= N <= 1,000,000)
输入中有几个测试用例。 每个案例包含一个整数N(2 <= N <= 1,000,000)
OutputOne line with a single integer for each case. If the number is a semi-prime number, then output "Yes", otherwise "No".
一行每个案件都有一个整数。 如果数字是半素数,则输出“是”,否则输出“否”。
Sample Input3
4
6
12
Yes
Yes
No
#include<stdio.h>
int a[1000002];int main()
{
int n,c,b,i,j,f;
a[0]=a[1]=1;
for(i=2;i<1000002;i++)
{
if(!a[i])
{
for(j=i+i;j<1000002;j+=i)
a[j]=1;
}
}
while(scanf("%d",&n)!=EOF)
{
f=0;
for(i=1;i<=(n/2);i++)
{
if(n%i==0)
{
b=i;c=n/i;
if(a[b]==0&&a[c]==0)
{
f=1;
break;
}
}
}
if(f==1)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}