题解 | #质数因子#

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int i = in.nextInt();
            List<Integer> set = digui(i, new ArrayList<>());
            Collections.sort(set);
            StringBuffer sbr = new StringBuffer();
            for (Integer integer : set) {
                sbr.append(integer).append(" ");
            }
            System.out.println(sbr.toString().substring(0, sbr.length() - 1));
        }
    }

    private static List<Integer> digui(Integer i, List<Integer> out) {
        double sqrt = Math.sqrt(i);
        boolean flag = false;
        for (int j = 2; j <= sqrt; j++) {
            if (i % j == 0) {
                out.add(j);
                i = i / j;
                flag = true;
                break;
            }
        }
        if (flag) {
            digui(i, out);
        } else {
            out.add(i);
        }
        return out;
    }
}