Load a Truck with the Most Units

### Problem Each row of `boxTypes` gives a number of available boxes and the units contained in each box of that type. The truck holds at most `truckSize` boxes regardless of type. Choose boxes to maximize their total units and return that total. ```cpp class Solution { public: int maximumUnits(vector<vector<int>>& boxTypes, int truckSize); }; ``` ### Examples **Example 1:** ```text boxTypes = [[2,5],[3,2]], truckSize = 3 Output: 12 Explanation: Take both five-unit boxes and one two-unit box. ``` **Example 2:** ```text boxTypes = [[1,8],[2,3]], truckSize = 5 Output: 14 Explanation: All three available boxes fit. ``` ### Constraints - `1 <= boxTypes.length <= 1000`. - Each box count and units-per-box value is in `[1,1000]`. - `1 <= truckSize <= 10^6`. ### Clarifying Questions The capacity counts boxes, not units or weight. Taking fewer than all boxes of a type is allowed. ```hint Inspect the structure What does one loaded box consume from capacity, and which quantities may be taken only in part? ``` ### Reasoning checkpoints - Respect both per-type availability and the truck's box-count capacity. - Prove maximal units even when the final selection uses only part of a type's stock. ### Optional extensions How could a frequency table over the bounded units-per-box range replace sorting?