LeetCode – Refresh – Largest Number

Corner case: when all the elements are 0. It should return "0", not  "00000000".

It use string to compare all the numbers.

class Solution {
public:
    string largestNumber(vector<int> &num) {
        int len = num.size();
        if (len == 0) return 0;
        vector<string> container;
        for (int i = 0; i < len; i++) {
            container.push_back(to_string(num[i]));
        }
        sort(container.begin(), container.end(), [](string &a, string &b){return a+b > b+a;});
        string result;
        for (int i = 0; i < len; i++) {
            result += container[i];
        }
        if (result[0] == '0') return "0";
        return result;
    }
};