view day2.rb @ 39:0e17e4bd97a9 default tip

Rewrite as four-dimensional route finding The grid isn't just a 2D grid. The constraints make it 4D: * X * Y * Last direction * Number of steps in that direction By tracking all four dimensions, we can find the shortest route for _all_ combinations of the constraint. Previously, we were dropping routes that were currently longer but ended up shorter because they could take subsequent steps that other routes couldn't.
author IBBoard <dev@ibboard.co.uk>
date Sun, 22 Sep 2024 11:30:53 +0100
parents 49dd1ae93696
children
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#! /usr/bin/env ruby

if ARGV.length != 4
        abort("Incorrect arguments - needs numbers for Red, Green and Blue then input file")
elsif not File.exist? (ARGV[3])
	abort("File #{ARGV[3]} did not exist")
end

max_colours = {
	"red" => ARGV[0].to_i,
	"green" => ARGV[1].to_i,
	"blue" => ARGV[2].to_i
}
file = ARGV[3]

sum = 0
File.open(file, "r").each_line do |line|
	game, all_picks = line.split(":")
	all_valid = all_picks.split(";").all? do |pick|
		pick.split(",").all? do |colour_pick|
			num_picked, colour_picked = colour_pick.strip.split(" ")
			# The last line of a Ruby block is the return value
			num_picked.to_i <= max_colours[colour_picked]
		end
	end
	if all_valid
		puts game
		sum += game.split(" ")[1].to_i
	end
end

puts sum