The easiest if not the only way to obtain “random but unique draws” is always going to be to do what we do in real life:   use a deck of cards.   Create a list of 0..99 and then List::Util::shuffle that list ... quite literally like shuffling a deck of cards and then using it just as you do use a deck of cards in real life.   You will shift the next number off the front of the list, and if you don’t like that one, simply push it onto the end and shift another.   Exactly like putting the card on the bottom of the deck and drawing another top-card.   (If it’s the same value, then the queue has degenerated to only one entry and you’re screwed ... you do need to test for that case and die.   Although the odds of this happening are astronomically tiny, Murphy’s Law decrees that it will happen during your first and/or your most important demo.)

The odds are 99 to 1 that the number you draw will be acceptable, so you can simply loop through the list so-far to see if for any reason the number you have selected is disqualified.

another.