1877. 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.

• Time : O(nlogn)
• Space : O(1)

class Solution {
public:
    int minPairSum(vector<int>& nums) {
        int res = 0;
        sort(nums.begin(), nums.end());
        for(int i = 0; i < nums.size() / 2; i++) {
            res = max(res, nums[i] + nums[nums.size() - 1 - i]);
        }
        return res;
    }
};