Today I have done leetcode's November LeetCoding Challenge with cpp.

November LeetCoding Challenge 17

Description

Minimize Maximum Pair Sum in Array

The pair sum of a pair (a,b) is equal to a + b. The maximum pair sum is the largest pair sum in a list of pairs.

• For example, if we have pairs (1,5), (2,3), and (4,4), the maximum pair sum would be max(1+5, 2+3, 4+4) = max(6, 5, 8) = 8.

Given an array nums of even length n, pair up the elements of nums into n / 2 pairs such that:

• Each element of nums is in exactly one pair, and
• The maximum pair sum is minimized.

Return the minimized maximum pair sum after optimally pairing up the elements.

Example 1:

Input: nums = [3,5,2,3]
Output: 7
Explanation: The elements can be paired up into pairs (3,3) and (5,2).
The maximum pair sum is max(3+3, 5+2) = max(6, 7) = 7.

Example 2:

Input: nums = [3,5,4,2,4,6]
Output: 8
Explanation: The elements can be paired up into pairs (3,5), (4,4), and (6,2).
The maximum pair sum is max(3+5, 4+4, 6+2) = max(8, 8, 8) = 8.

Constraints:

• n == nums.length
• 2 <= n <= 105
• n is even.
• 1 <= nums[i] <= 105

Solution

auto speedup = []() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int minPairSum(vector<int>& nums) {
    sort(nums.begin(), nums.end());
    int len = nums.size();
    int answer = 0;
    for(int i = 0; i * 2 < len; ++i) {
      answer = max(answer, nums[i] + nums[len - i - 1]);
    }
    return answer;
  }
};

// Accepted
// 37/37 cases passed (154 ms)
// Your runtime beats 97.75 % of cpp submissions
// Your memory usage beats 61.58 % of cpp submissions (96.5 MB)