[LeetCode]179. Largest Number

Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.

思路：

[3,30,34,5,9] -> [9,5,3,43,30] ->[9534330]

将数组里的每一个String排序，然后按照从大到小的顺序从StringBuffer里

    public String largestNumber(int[] nums) {                String[] arr=new String[nums.length];        for(int i=0;i<nums.length;i++){            arr[i]=nums[i]+"";        }        Arrays.sort(arr,new Comparator<String>(){            public int compare(String i,String j){                  String s1 = i+j;                  String s2 = j+i;                return s1.compareTo(s2);            }        });        if(arr[arr.length-1].charAt(0)=='0'){            return "0";        }        StringBuffer sb=new StringBuffer();        for(int i=arr.length-1;i>=0;i--){            sb.append(arr[i]);        }        return sb.toString();          }