Each entry of stock is [item, quantity, minimum]. An item needs restocking when its
quantity is strictly below its minimum. Return a list of [item, needed] for every such
item, where needed = minimum - quantity, in the same order as the input.
Examples
Input: stock = [["nails", 3, 10], ["screws", 20, 10], ["glue", 5, 5]]
Output: [["nails", 7]]
Input: stock = []
Output: []
Constraints
0 <= len(stock) <= 1000,0 <= quantity, minimum <= 10**4
Goals
- Filter records that meet a condition while keeping their order
- Compute a derived value (the shortfall) for each selected record