Largest Number

class Solution {
public:
    string largestNumber(vector<int>& nums) {
        vector<string> s;
        s.reserve(nums.size());
        for (int x : nums) s.push_back(to_string(x));
        sort(s.begin(), s.end(), [](const string& a, const string& b) {
            return a + b > b + a;
        });
        if (s[0] == "0") return "0";  // all zeros
        string out;
        for (auto& t : s) out += t;
        return out;
    }
};

import (
    "sort"
    "strconv"
    "strings"
)

func largestNumber(nums []int) string {
    s := make([]string, len(nums))
    for i, x := range nums {
        s[i] = strconv.Itoa(x)
    }
    sort.Slice(s, func(i, j int) bool {
        return s[i]+s[j] > s[j]+s[i]
    })
    if s[0] == "0" {
        return "0"
    }
    return strings.Join(s, "")
}

from functools import cmp_to_key
from typing import List

class Solution:
    def largestNumber(self, nums: List[int]) -> str:
        s = [str(x) for x in nums]

        def cmp(a: str, b: str) -> int:
            if a + b > b + a:
                return -1
            if a + b < b + a:
                return 1
            return 0

        s.sort(key=cmp_to_key(cmp))
        if s[0] == "0":
            return "0"
        return "".join(s)

function largestNumber(nums) {
    const s = nums.map(String);
    s.sort((a, b) => {
        if (a + b > b + a) return -1;
        if (a + b < b + a) return 1;
        return 0;
    });
    if (s[0] === "0") return "0";
    return s.join('');
}

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

function largestNumber(nums: number[]): string {
    const s = nums.map(String);
    s.sort((a, b) => {
        if (a + b > b + a) return -1;
        if (a + b < b + a) return 1;
        return 0;
    });
    if (s[0] === "0") return "0";
    return s.join('');
}