view day6.rb @ 33:676461cc3a70

Day 23 - track segments, not each space This allows us to explore the branches once then do quicker calculations for valid route lengths. But still requires exploring 1,262,816 routes to find the longest!
author IBBoard <dev@ibboard.co.uk>
date Thu, 04 Jan 2024 14:52:24 +0000
parents 51e5f26dc81e
children
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#! /usr/bin/env ruby

if ARGV.length != 1
        abort("Incorrect arguments - needs input file")
elsif not File.exist? (ARGV[0])
	abort("File #{ARGV[0]} did not exist")
end

file = ARGV[0]

times, distances = File.open(file, "r").each_line(chomp: true).map {|v| puts v; puts v.split(":"); v.split(":")[1].split(" ").map(&:to_i)}
events = times.zip(distances)

product = events.map do |event|
	mid = (event[0].to_f / 2).floor
	first_success = (1..mid).bsearch {|i| (event[0] - i) * i > event[1]}
	num_success = (mid - first_success + 1) * 2
	event[0].odd? ? num_success : num_success - 1
end.reduce(:*)

puts product