2656. Maximum Sum With Exactly K Elements

You are given a 0-indexed integer array nums and an integer k. Your task is to perform the following operation exactly k times in order to maximize your score:

1. Select an element m from nums.
2. Remove the selected element m from the array.
3. Add a new element with a value of m + 1 to the array.
4. Increase your score by m.

Return the maximum score you can achieve after performing the operation exactly k times.

class Solution {
public:
    int maximizeSum(vector<int>& nums, int k) {
        int ma = *max_element(begin(nums), end(nums));
        return k * (ma + ma + k - 1) / 2;
    }
};