[BaekJoon][6588] 골드바흐의 추측

BAEKJOON ONLINE JUDGE

6588 골드바흐의 추측

https://www.acmicpc.net/problem/6588

#include <stdio.h>
 
int prime[1000001];
 
void checkprime()
{
    int i, j;
 
    for (i = 2; i < 1000001; i++)     prime[i] = 1;
    for (i = 2; i * i < 1000001; i++) {
        for (j = 2; prime[i] && i * j < 1000001; j++)
            prime[i * j] = 0;
    }
}
 
int main()
{
    int n;
    int i;
 
    checkprime();
 
    while (scanf("%d", &n) && n) {
        for (i = 3; i * 2 <= n; i += 2) {
            if (prime[i] && prime[n - i]) {
                printf("%d = %d + %d\n", n, i, n - i);
                break;
            }
        }
    }
 
    return 0;
}