Advent 2015 day 9

9.rb

require "json"
require "byebug"

mapping = {}

list = File.read("9_input.txt").lines.map(&:chomp)

list.each do |l|
  a, _, b, _, number = l.split(" ")
  mapping[[a, b]] = number.to_i
  mapping[[b ,a]] = number.to_i
end

min = Float::INFINITY
max = -Float::INFINITY

mapping.keys.flatten.uniq.permutation.each do |permutation|
  sum = permutation.each_cons(2).sum do |a, b|
    mapping[[a, b]]
  end

  min = [min, sum].min
  max = [max, sum].max
end

puts "min: #{min}"
puts "max: #{max}"

9_mini.rb

require "json"

mapping = File.read("9_input.txt").lines.map(&:chomp).inject({}) do |hash, line|
  a, _, b, _, number = line.split(" ")
  hash[[a, b].sort] = number.to_i
  hash
end

distances = mapping.keys.flatten.uniq.permutation.map do |permutation|
  permutation.each_cons(2).sum { |a,b| mapping[[a,b].sort]}
end

puts "min: #{distances.min}"
puts "max: #{distances.max}"