Advent of Code, day 16

day16_part1.rb

#!/usr/bin/env ruby

# http://adventofcode.com/day/16

Sue = Struct.new(:id, :attrs)

sues = File.read("input").each_line.map do |line|
  id = Integer(line[/(\d+)/])
  attrs = Hash[
    line.scan(/(\w+): (\d+)/).map do |key, value|
      [key.to_sym, Integer(value)]
    end
  ]
  Sue.new(id, attrs)
end

KNOWN_ATTRS = {
  children: 3,
  cats: 7,
  samoyeds: 2,
  pomeranians: 3,
  akitas: 0,
  vizslas: 0,
  goldfish: 5,
  trees: 3,
  cars: 2,
  perfumes: 1,
}

def matches_known_attrs(sue)
  sue.all? do |key, value|
    KNOWN_ATTRS[key] === value
  end
end

gifter_number = sues.find do |sue|
  matches_known_attrs(sue.attrs)
end.id
puts gifter_number

day16_part2.rb

#!/usr/bin/env ruby

# http://adventofcode.com/day/16

Sue = Struct.new(:id, :attrs)

sues = File.read("input").each_line.map do |line|
  id = Integer(line[/(\d+)/])
  attrs = Hash[
    line.scan(/(\w+): (\d+)/).map do |key, value|
      [key.to_sym, Integer(value)]
    end
  ]
  Sue.new(id, attrs)
end

def eq(target)
  ->(n) { n == target }
end

def gt(target)
  ->(n) { n > target }
end

def lt(target)
  ->(n) { n < target }
end

KNOWN_ATTRS = {
  children: eq(3),
  cats: gt(7),
  samoyeds: eq(2),
  pomeranians: lt(3),
  akitas: eq(0),
  vizslas: eq(0),
  goldfish: lt(5),
  trees: gt(3),
  cars: eq(2),
  perfumes: eq(1),
}

def matches_known_attrs(sue)
  sue.all? do |key, value|
    KNOWN_ATTRS[key].(value)
  end
end

gifter_number = sues.find do |sue|
  matches_known_attrs(sue.attrs)
end.id
puts gifter_number