题解 | 查找组成一个偶数最接近的两个素数

#include <iostream>
#include <cmath>
using namespace std;

bool is_sunumber(int n);
void find_two(int n);
int main() {
    int num;
    cin >> num;
    
   find_two(num);

}
bool is_sunumber(int num){//判断一个数是不是素数
    if (num <= 1) return false;
    if (num == 2) return true;
    if (num % 2 == 0) return false;
    for (int i = 3; i <= std::sqrt(num); i += 2) {
        if (num % i == 0) return false;
    }
    return true;
}
void find_two(int n){//找最小的素数对并输出
    int num1,num2;
    int min_diff=n;
    for(int i=2 ; i<=n/2 ; i++){
        int j = n - i;
        if(is_sunumber(i) && is_sunumber(j)){
            int diff = std::abs(i-j);
            if(min_diff > diff){
                min_diff = diff;
                num1 = i;
                num2 = j;
            }
        }
    }
    cout << num1 << endl;
    cout << num2 << endl;
}