#leetcode#Largest Number

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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.

考察Comparator的用法，注意一个小陷阱，当input为{0，0}时，sort之后得到的是“00”，此时应该判断stringbuilder首字符是否为‘0’，如果是‘0’则直接返回“0”

public class Solution {    public String largestNumber(int[] nums) {        if(nums == null || nums.length == 0)            return "";                    Comparator<String> comp = new Comparator<String>(){            @Override            public int compare(String a, String b){                return (a + b).compareTo(b + a);            }        };                String[] strs = new String[nums.length];        for(int i = 0; i < nums.length; i++){            strs[i] = String.valueOf(nums[i]);        }        Arrays.sort(strs, comp);        StringBuilder sb = new StringBuilder();        for(int i = nums.length - 1; i >= 0; i--){            sb.append(strs[i]);        }                return sb.charAt(0) == '0' ? "0" : sb.toString();    }}

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