Leaderboard Positions - Part 1: 1167, Part 2: 1096
Hello all! In this puzzle, we need to find every set of numbers where if we place specific operations between them, we get the expect value. In
the input, we are given two things: a value, and a list of numbers. If we can find a set of operations, then we add it to a sum. Note that order
of operations does not matter here. In part 1, we need to use + and *. For example...
3267: 81 40 27
works for
81 * 40 + 27 = 3267
To find a set of operations that work, we can simulate every possible operation until we find a match. To make this somewhat efficient, we can
use binary numbers as it will generate every possible combination of operations. If we generate each binary representation from 0 to
2^(list_len - 1), we can treat 0 as addition, and 1 as multiplication. In part 2, we do a similar thing
except we need to add concatenation into the operator list. This bumps us from binary numbers to tenary numbers. However, because the list
lengths are small enough (the biggest list size is 12, and 2^12 = 4096 and 3^12 = 531441), we can use the same
approach.
EDIT: I have implemented both an iterative and recursive solution, and the recursive one is faster, so I will keep with that!