题解 | #查找组成一个偶数最接近的两个素数#

#include <stdio.h>

int isprime(int n) {
    int cnt = 0;
    if (n == 2 || n == 3) {
        return 1;
    }
    for (int i = 3; i < n; i += 2) {
        if (n % i == 0) {
            return 0;
        }
    }
    return 1;
}

int main() {

    int n = 0;
    int a[1000] = {0};
    scanf("%d", &n);
    a[2] = 2;
    for (int i = 3; i < n; i += 2) {
        if (isprime(i)) {
            a[i] = i;
        }

    }

    /*for (int i = 0; i < 54; i++) {
        if (a[i]) {
            printf("%d ", a[i]);
        }
    }
    printf("\n");*/

    int min = 1000;
    int temp = 0;
    int i = 0;
    int j = 0;
    int x = 0;
    int y = 0;

    for (i = 2; i < 1000; i++) {
        if (a[i] == 0) {
            continue;
        }
        for (j = 2; j < 1000; j++) {
            if (a[j] == 0) {
                continue;
            }
            if (a[i] + a[j] == n) {
                temp = a[j] - a[i];
                temp = temp > 0 ? temp : -temp;
                if (temp < min) {
                    min = temp;
                    x = i;
                    y = j;
                }
            }
        }
    }
    printf("%d\n%d", x, y);

    return 0;
}