任意正整数求质因子

。

import java.util.*;

public class Main{

public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    Long aLong = scanner.nextLong();

    int a = (int) Math.sqrt(aLong) + 1;
    int i = 2;
    while (aLong != 1 && i <= a) {
        if (aLong % i == 0) {
            aLong /= i;
            System.out.print(i + " ");
            i = 2;
        } else {// 单纯暴力,可以优化为i只包含 '奇数(不含1)' 和'2',我懒
            i++;
        }
    }
    if (i > a) {// 在2-->sqrt(n)中,无因数,输出自身
        System.out.print(aLong + " ");
    }
    scanner.close();
}

}