https://github.com/billyb2/quantum-developer-contests/blob/master/comp-contest-%239.html
Saves as much computation power as possible by limiting the amount of operations.

Also works for negative multiplication.

Unfortuantely, it's slows down for much larger numbers, and is in general slower since it runs in the browser. It tries to improve efficiency as well as possible, however, by having adding the larger number to itself instead of just picking the first number.