【leetocde】179. Largest number

/**
* @author          johnsondu
* @problem         Largest Number
* @url             https://leetcode.com/problems/largest-number/ * @timeComlexity   O(n)
* @spaceComplexity O(n)
* @strategy        using sort to compare
*/

#include <algorithm>
class Solution {
public:
static bool cmp(const string &a, const string &b) {
return (a + b) > (b + a);
}

string largestNumber(vector<int>& nums) {
int n = nums.size();
vector<string> vec;
for(int i = 0; i < n;  i ++) {
vec.push_back(to_string(nums[i]));
}

sort(vec.begin(), vec.end(), cmp);

string ans("");
for(int i = 0; i < n; i ++) {
ans += vec[i];
}
return (ans[0] == '0' ? "0" : ans);
}
};