Take from Stock - codepath/compsci_guides GitHub Wiki

Unit 2 Session 2 (Click for link to problem statements)

U-nderstand

Understand what the interviewer is asking for by using test cases and questions about the problem.

• What if I reduce an items stock to exactly 0?
  • In that case, remove the item from the dictionary -- stock should always be 1 or higher.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Check if the operation is valid, and if so, deduct the stock and return the updated dict.

1) If the item does not exist, return an error message
2) If the quantity requested > stock, return an error message
3) Reduce the item stock by the requested quantity
4) If the stock is reduced to zero, remove from items dict
5) Return updated items dict

I-mplement

def pop_stock(items, item_name, quantity):
    if item_name not in items:
        return "Item does not exist."
    if quantity > items[item_name]:
        return "Not enough stock."
    items[item_name] -= quantity
    if items[item_name] <= 0:
        items.pop(item_name)
    return items