aoc-2022/3.rb

require 'set'

@input = File.read("3.input").split("\n")

def prio(char)
  if char.ord >= 'a'.ord then
    return char.ord - 'a'.ord + 1
  else
    return char.ord - 'A'.ord + 27
  end
end

def part1()
  score = 0

  for sack in @input do
    left, right = sack.slice(0, sack.length / 2), sack.slice(sack.length / 2, sack.length)

    right.each_char do |char|
      if left.include? char then
        score += prio(char)
        break
      end
    end
  end

  puts score
end

def part2()
  score = 0

  @input.each_slice(3) do |group|
    sets = group.map {|sack| Set.new(sack.chars)}

    result = sets[0] & sets[1] & sets[2]

    score += prio(result.to_a[0])
  end

  puts score
end

part1()
part2()