题目：

输入一个正整数数组，把数组里所有数字拼接起来排成一个数。打印能拼接出所有数字中最小的一个。

 

解答：

 1 public class Solution {
 2 
 3     public static void main(String[] args) {
 4         int[] array = {321,32,3};
 5         printMin(array);
 6     }
 7 
 8     private static void printMin(int[] array) {
 9         int[] clone = array.clone();
10         printMin(clone, 0, clone.length-1);
11         for(int i: clone) {
12             System.out.print(i);
13         }
14     }
15 
16     private static void printMin(int[] array, int start, int end) {
17         if(start < end) {
18             int main_number = array[end];
19             int small_cur = start;
20             for(int j = start; j < end; j++) {
21                 if(isSmall(String.valueOf(array[j]), String.valueOf(main_number))) {
22                     int temp = array[j];
23                     array[j] = array[small_cur];
24                     array[small_cur] = temp;
25                     small_cur++;
26                 }
27             }
28 
29             array[end] = array[small_cur];
30             array[small_cur] = main_number;
31             printMin(array, 0, small_cur-1);
32             printMin(array, small_cur+1, end);
33         }
34     }
35 
36     public static boolean isSmall(String m, String n) {
37         String left = m + n;
38         String right = n + m;
39 
40         boolean result = false;
41         for(int i = 0; i < left.length(); i++) {
42             if(left.charAt(i) < right.charAt(i)) {
43                 return true;
44             } else if(left.charAt(i) > right.charAt(i)) {
45                 return false;
46             }
47         }
48 
49         return result;
50     }
51 }