Maximize the Sum of Pair Minima

### Problem Partition the 2n elements of nums into n pairs, using every occurrence once. Return the greatest possible sum of the smaller value in each pair. ```cpp class Solution { public: int arrayPairSum(vector<int>& nums); }; ``` ### Examples **Example 1:** ```text nums = [8,1,7,2] Output: 8 Explanation: Pair (1,2) and (7,8), giving 1+7. ``` **Example 2:** ```text nums = [-4,-1,2,3] Output: -2 Explanation: Adjacent sorted pairs contribute -4+2. ``` ### Constraints - For n in 1..10000 there are exactly 2n input entries. Values are in -10000..10000. ### Clarifying Questions Use all occurrences exactly once and justify why pairing the two smallest remaining values is safe. ```hint Read the boundary condition Can a pairing of the smallest two values be exchanged into any optimum? ``` ### Contract considerations Use all occurrences exactly once and justify why pairing the two smallest remaining values is safe.