【蓝桥杯】历届试题 回文数字

 1 import java.util.Scanner;
 2 
 3 public class Main {
 4 
 5     public static void main(String[] args) {
 6         Scanner sc = new Scanner(System.in);
 7         int n = sc.nextInt();
 8         int[] a = new int[7];
 9         a[4] = 1;
10         boolean flag = false;
11         while (a[6] != 1) {
12             int k = 6;
13             while (a[k] == 0)
14                 k--;
15             boolean isHws = true;
16             for (int i = 0; i <= k; i++)// 搜索回文数
17             {
18                 if (a[i] != a[k - i]) {
19                     isHws = false;
20                     break;
21                 }
22             }
23             if (isHws)// 如果是回文数则看各位和是否等于N
24             {
25                 int sum = 0;
26                 for (int i = 0; i <= k; i++)
27                     sum += a[i];
28                 if (sum == n) {
29                     for (int i = 0; i <= k; i++)
30                         System.out.print(a[i]);
31                     System.out.println();
32                     flag = true;
33                 }
34             }
35             a[0]++;
36             k = 0;
37             while (a[k] >= 10)// 可以理解为“进位”
38             {
39                 a[k] -= 10;
40                 a[k + 1]++;
41                 k++;
42             }
43         }
44         if (!flag)
45             System.out.println("-1");
46     }
47 
48 }