It's pretty confusing just by seeing this project, but a bloom filter is an efficient way to tell for sure if an item is not in a set. For more information, see this: https://en.wikipedia.org/wiki/Bloom_filter I made this array 9 bit, but it could be anything. You might have to change the hash function though.
Credit to wikipedia for information For more information, see this: https://en.wikipedia.org/wiki/Bloom_filter