Construct minimum number by reordering a given non-negative integer array. Arrange them such that they form the minimum number.
The result may be very large, so you need to return a string instead of an integer.
Given [3, 32, 321], there are 6 possible numbers can be constructed by reordering the array:
3+32+321=332321
3+321+32=332132
32+3+321=323321
32+321+3=323213
321+3+32=321332
321+32+3=321323
So after reordering, the minimum number is 321323, and return it.
分析：
这里需要对数组进行排序，那么怎么比较大小呢？对于数A和B，如果AB在一起组成的数小于BA组成的数，我们就认为A<B,反之亦然。
1 public static String minNumber(int[] nums) { 2 if (nums == null || nums.length == 0) 3 return ""; 4 5 String[] strs = new String[nums.length]; 6 for (int i = 0; i < nums.length; i++) { 7 strs[i] = String.valueOf(nums[i]); 8 } 9 10 Arrays.sort(strs, new Comparator<String>() { 11 public int compare(String str1, String str2) { 12 return (str1 + str2).compareTo(str2 + str1); 13 } 14 }); 15 16 StringBuilder sb = new StringBuilder(); 17 for (String str : strs) { 18 sb.append(str); 19 } 20 for (int i = 0; i < sb.length(); i++) { 21 if (sb.charAt(i) != ‘0‘) { 22 return sb.substring(i); 23 } 24 } 25 return "0"; 26 }
Reorder array to construct the minimum number
原文：http://www.cnblogs.com/beiyeqingteng/p/5874164.html