Largest Number

bool compare(const string &a,const string &b){
    if(a+b>b+a) return true;
    return false;
}
class Solution {
public:
    string largestNumber(vector<int>& nums) {
        vector<string> arr;
        for(auto itr:nums){
            arr.push_back(to_string(itr));
        }
        sort(arr.begin(),arr.end(),compare);
        string ans="";
        for(auto itr:arr) ans+=itr;
        if(ans[0]=='0') return "0";
        return ans;
    }
};

#Python
def fun(a,b):
    return -1 if a+b>b+a else 1

class Solution:
    def largestNumber(self, nums: List[int]) -> str:
        nums=[str(i) for i in nums]
        nums.sort(key=cmp_to_key(fun))
        if nums[0][0]=='0':
            return "0"
        return ''.join(nums)