AoC2021/day02/solution.rb

#!/bin/env ruby

commands = File.readlines('./input').map(&:split).map { [_1.to_sym, _2.to_i] }
# Part 1
dist = 0
depth = 0
commands.each do |command, unit|
  case command
  when :forward
    dist += unit
  when :down
    depth += unit
  when :up
    depth -= unit
  end
end

p dist * depth

# Part 2
dist = 0
depth = 0
aim = 0
commands.each do |command, unit|
  case command
  when :forward
    depth += aim * unit
    dist += unit
  when :down
    aim += unit
  when :up
    aim -= unit
  end
end

p dist * depth