## [179\. Largest Number](https://leetcode.com/problems/largest-number/)

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`

class Solution {
public:
    string largestNumber(vector<int>& nums) {
        int n = nums.size();

        vector<string> strNums(n);
        
        // 元素轉成 string
        for (int i = 0; i < n; ++i) {
            strNums[i] = to_string(nums[i]);
        }

        sort(strNums.begin(), strNums.end(),
             [](string& a, string& b) { return a + b > b + a; });

        // 因為已經從大排到小了，最前面如果是 0，就直接返回 0
        if (strNums[0] == "0") {
            return "0";
        }

        string res;
        for (string s : strNums) res += s;

        return res;        
    }
};

:::success
- 時間複雜度：$O(N \cdot N)$
- 空間複雜度：$O(N)$
:::