Here’s the scenario: you have a large collection of various small value stamps, $0.01, $0.04, $0.24, $0.41, and so on. Now you need to pay some postage on a package valued at, say, $3.64. How do you figure out which stamps to use?
The algorithm proceeds like this,
1. Use google to find someone’s else implementation,
2. Use their postage stamp calculator.
3. Drink a beer instead of wasting your time writing an algorithm someone else has already written.