You are tasked with storing a certain number of boxes in a storage room. You are given a 2D array, boxTypes, where boxTypes[i] = [numberOfBoxes_i,numberOfUnitsPerBox_i] :

$numberOfBoxes i$ represents the number of boxes of type i.

$numberOfUnitsPerBox i$ indicates the number of units each box of type i contains.

Additionally, you are given an integer storageCapacity, which defines the maximum number of boxes that can be placed in the storage room. You can select any combination of boxes as long as the total number of boxes does not exceed storageCapacity.

Return the maximum total number of units that can be stored in the storage room.

Example 1:

Input: boxTypes = [[2,5], [3,4], [1,6]], storageCapacity = 5
Output: 24

Explanation:
There are 2 boxes of type 1, each with 5 units.
There are 3 boxes of type 2, each with 4 units.
There is 1 box of type 3, which contains 6 units.

To maximize the total number of units, we prioritize box types with more units per box.
Take 1 box of type 3 → 1 × 6 = 6 units
Take 2 boxes of type 1 → 2 × 5 = 10 units
Take 2 boxes of type 2 → 2 × 4 = 8 units

Total boxes used: 1 + 2 + 2 = 5 (fits the storage capacity)
Total units: 6 + 10 + 8 = 24

Example 2:

Input: boxTypes = [[4,8], [1,9], [3,7], [2,10]], storageCapacity = 6
Output: 53

Explanation:
To maximize the total units, we sort the box types by units per box in descending order:
Sorted boxTypes: [[2,10], [1,9], [4,8], [3,7]]

Now, select boxes greedily until we reach the storage capacity:
Take 2 boxes of type [2,10] → 2 × 10 = 20 units
Take 1 box of type [1,9] → 1 × 9 = 9 units
Take 3 boxes of type [4,8] → 3 × 8 = 24 units

Total boxes used: 2 + 1 + 3 = 6
Total units: 20 + 9 + 24 = 53

Example 3:

Input: boxTypes = [[5,10], [2,5]], storageCapacity = 10
Output: 60

Explanation:
The storage capacity is larger than the total number of available boxes.
Take all 5 boxes of type [5,10] -> 5 × 10 = 50 units
Take all 2 boxes of type [2,5] -> 2 × 5 = 10 units

Total boxes used: 5 + 2 = 7
Total units: 50 + 10 = 60

Constraints

1 <= boxTypes.length <= 1000
1 <= numberOfBoxes_i <= 1000
1 <= numberOfUnitsPerBox_i <= 1000
1 <= storageCapacity <= 10⁶

37. Maximum Units in Storage