题解 | #质数因子#

import java.util.*;

public class Main { public static void main(String args[]) { Scanner sc = new Scanner(System.in); int num = sc.nextInt(); StringBuilder sb = new StringBuilder(); for (int i = 2; i * i <= num; i++) { while (num % i == 0) { if (i <= 3) { sb.append(i).append(" "); num /= i; continue; }

            boolean isAdd = true;
            for (int j = 2; j * j <= i; j++) {
                if (i % j == 0) {
                    isAdd = false;
                    break;
                }
            }
            if (isAdd) {
                sb.append(i).append(" ");
            }
            num /= i;
        }
    }

    if (num != 1) {
        sb.append(num);
    }

    System.out.print(sb);
}

}