#!/usr/bin/env ruby

deltas = {}
whos = []

File.readlines("day13.input").map(&:strip).each do |line|
  who, dir, delta, neighbour = line.scan(/(\w+) would (gain|lose) (\d+) happiness units by sitting next to (\w+)\./)[0]
  delta = delta.to_i
  delta = -delta if dir == "lose"
  deltas[who] = {} if deltas[who].nil?
  deltas[who][neighbour] = delta
  whos << who
end

whos.uniq!
num = whos.length

change = whos.permutation.map { |perm|
  num.times.map { |i|
    left = (i - 1) % num
    right = (i + 1) % num
    [deltas[perm[i]][perm[left]], deltas[perm[i]][perm[right]]]
  }.flatten.sum
}.max

puts "Part 1: #{change}"

deltas["me"] = {}
whos.each do |who|
  deltas["me"][who] = 0
  deltas[who]["me"] = 0
end

whos << "me"
num += 1

change = whos.permutation.map { |perm|
  num.times.map { |i|
    left = (i - 1) % num
    right = (i + 1) % num
    [deltas[perm[i]][perm[left]], deltas[perm[i]][perm[right]]]
  }.flatten.sum
}.max

puts "Part 2: #{change}"