# 179. Largest Number

## Description

Given a list of non-negative integers nums, arrange them such that they form the largest number and return it.

Since the result may be very large, so you need to return a string instead of an integer.

Example 1:

Input: nums = [10,2]
Output: "210"


Example 2:

Input: nums = [3,30,34,5,9]
Output: "9534330"


Constraints:

• 1 <= nums.length <= 100
• 0 <= nums[i] <= 109

## Solutions

• class Solution {
public String largestNumber(int[] nums) {
List<String> vs = new ArrayList<>();
for (int v : nums) {
}
vs.sort((a, b) -> (b + a).compareTo(a + b));
if ("0".equals(vs.get(0))) {
return "0";
}
return String.join("", vs);
}
}

• class Solution {
public:
string largestNumber(vector<int>& nums) {
vector<string> vs;
for (int v : nums) vs.push_back(to_string(v));
sort(vs.begin(), vs.end(), [](string& a, string& b) {
return a + b > b + a;
});
if (vs[0] == "0") return "0";
string ans;
for (string v : vs) ans += v;
return ans;
}
};

• class Solution:
def largestNumber(self, nums: List[int]) -> str:
nums = [str(v) for v in nums]
nums.sort(key=cmp_to_key(lambda a, b: 1 if a + b < b + a else -1))
return "0" if nums[0] == "0" else "".join(nums)


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

• using System;
using System.Globalization;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class Comparer: IComparer<string>
{
public int Compare(string left, string right)
{
return Compare(left, right, 0, 0);
}

private int Compare(string left, string right, int lBegin, int rBegin)
{
var len = Math.Min(left.Length - lBegin, right.Length - rBegin);
for (var i = 0; i < len; ++i)
{
if (left[lBegin + i] != right[rBegin + i])
{
return left[lBegin + i] < right[rBegin + i] ? -1 : 1;
}
}

if (left.Length - lBegin == right.Length - rBegin)
{
return 0;
}
if (left.Length - lBegin > right.Length - rBegin)
{
return Compare(left, right, lBegin + len, rBegin);
}
else
{
return Compare(left, right, lBegin, rBegin + len);
}
}
}

public class Solution {
public string LargestNumber(int[] nums) {
var sb = new StringBuilder();
var strs = nums.Select(n => n.ToString(CultureInfo.InvariantCulture)).OrderByDescending(s => s, new Comparer());

var nonZeroOccurred = false;
foreach (var str in strs)
{
if (!nonZeroOccurred && str == "0") continue;
sb.Append(str);
nonZeroOccurred = true;
}
return sb.Length == 0 ? "0" : sb.ToString();
}
}