Speeding up the cost search

Adding day07 part 2

Simplifying logic

Adding day07 part 1

Adding initial day07 files

Co-authored-by: Ryan Reed <git@ryanreed.net>
Reviewed-on: https://gitea.ryanreed.net:3000/ryanreed/aoc2021/pulls/7
Co-Authored-By: Ryan Reed <ryanreed@noreply.gitea.ryanreed.net>
Co-Committed-By: Ryan Reed <ryanreed@noreply.gitea.ryanreed.net>