题解 | #质数因子#

#include <stdio.h>

int main() {
    long long num;
    scanf("%lld", &num);

    for(long long i=2; i*i <= num; i++){     //i*i来做剪枝，质因子的平方必定小于num
        if(num%i == 0){
            printf("%d ", i);
            num = num/i;
            if(num%i == 0)
                i--;   
        }
    }
    if(num != 1)        //如果最后num不为1，所以num为质因子
        printf("%d", num);
    return 0;
}