#!/usr/bin/env ruby # frozen_string_literal: true require "pathname" Item = Struct.new(:name, :speed, :active_time, :recovery_time) def parse_file(file) file.each_line.map do |line| line.partition(" can fly ") => [name, _, tail] tail.partition(" km/s for ") => [speed, _, tail] tail.partition(" seconds, but then must rest for ") => [active_time, _, tail] tail.split.first => recovery_time Item.new(name, speed.to_i, active_time.to_i, recovery_time.to_i) end end def race(items, time) active_times = items.map { |i| [i, 1..i.active_time] }.to_h (1..time).each_with_object(items.map {|i| [i, {score: 0, distance: 0}] }.to_h) do |sec, stats| stats.each do |item, stat| active = active_times[item] stat[:distance] += item.speed if active.include?(sec) next unless sec > active.last active_start = sec + item.recovery_time active_end = active_start - 1 + item.active_time active_times[item] = active_start..active_end end leading = stats.values.max_by { |v| v[:distance] }[:distance] stats.each do |n, s| s[:score] += 1 if s[:distance] == leading end end end def main(file_paths) file_paths.each do |file_path| puts "File: #{file_path}" items = parse_file(file_path) results = race(items, 2503) results.values.max_by { |v| v[:distance] } => {distance:} puts "solution 1: #{distance}" results.values.max_by { |v| v[:score] } => {score:} puts "solution 2: #{score}" end end main(ARGV.map { |x| Pathname(x) })