[leetcode] Largest Number

From : https://leetcode.com/problems/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.

class Solution {public:    static int comp(int a, int b) {string sa = to_string(a);string sb = to_string(b);return sa+sb > sb+sa;    }    string largestNumber(vector<int>& nums) {        if(nums.size() == 0) return "";sort(nums.begin(), nums.end(), comp);        string ans = "";        for(int i=0, l=nums.size(); i<l; i++) {ans += to_string(nums[i]);        }        if(ans[0] == '0') return "0";        return ans;    }};

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