Note: 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"

Example 3:

Input: nums = [1]
Output: "1"

Example 4:

Input: nums = [10]
Output: "10"

Constraints:

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

Solution: Greedy

Sort numbers by lexical order.
e.g. 9 > 666

Time complexity: O(nlogn)
Space complexity: O(n)

// Author: Huahua
class Solution {
public:
  string largestNumber(vector<int> &num) {
    vector<string> s;
    for (int x : num)
      s.emplace_back(to_string(x));
    sort(begin(s), end(s), [](const auto& s1, const auto& s2) {
      return s1 + s2 > s2 + s1;
    });
    if (s[0] == "0") return "0";
    string ans;
    for (int i = 0; i < s.size(); ++i)
      ans += s[i];
    return ans;
  }
};

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