数字黑洞(Java)

解题思路:

注意事项:

参考代码:

import java.util.Arrays;

import java.util.Scanner;

public class Main{

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

int count = 0;

while (true) {

if (n == 6174) {

break;

}

String[] arr = new String[4];

arr[0] = n / 1000 + "";

arr[1] = n / 100 % 10 + "";

arr[2] = n / 10 % 10 + "";

arr[3] = n % 10 + "";

int[] arr1 = new int[4];

for (int i = 0; i < arr1.length; i++) {

arr1[i] = Integer.parseInt(arr[i]);

}

Arrays.sort(arr1);

int max = 0;

int min = 0;

String str = "";

for (int i = 0; i < arr1.length; i++) {

str += arr1[i];

}

min = Integer.parseInt(str);

for (int i = 0; i < arr1.length - 1; i++) {

for (int j = 0; j < arr1.length - 1 - i; j++) {

if (arr1[j] < arr1[j + 1]) {

int a = arr1[j];

arr1[j] = arr1[j + 1];

arr1[j + 1] = a;

}

}

}

String str1 = "";

for (int i = 0; i < arr1.length; i++) {

str1 += arr1[i];

}

max = Integer.parseInt(str1);

n = max - min;

count++;

}

System.out.println(count);

}

}