Day 21 Ruby solutions

Author: creideiki

21-1.rb

@@ -0,0 +1,47 @@
+#!/usr/bin/env ruby
+
+$monkeys = {}
+
+class Monkey
+  def initialize(name, operation)
+    number_format = /^(?<num>[[:digit:]]+)$/
+    calc_format = /^(?<m1>[[:alpha:]]+) (?<op>[-+*\/]) (?<m2>[[:alpha:]]+)$/
+
+    @operation = operation
+    @name = name
+    @value = nil
+
+    if m = number_format.match(@operation)
+      @value = m['num'].to_i
+    else
+      m = calc_format.match(@operation)
+      @m1 = m['m1']
+      @op = m['op']
+      @m2 = m['m2']
+    end
+  end
+
+  def value
+    return @value if @value
+
+    @value = $monkeys[@m1].value.send(@op, $monkeys[@m2].value)
+  end
+
+  def to_s
+    "<#{self.class}: #{@name} = #{@operation} (#{@value})>"
+  end
+
+  alias inspect to_s
+end
+
+
+input = File.read('21.input').lines
+
+monkey_format = /^(?<name>[[:alpha:]]+): (?<op>.*)$/
+
+input.each do |line|
+  m = monkey_format.match line
+  $monkeys[m['name']] = Monkey.new(m['name'], m['op'])
+end
+
+print $monkeys['root'].value, "\n"

21-2.rb

@@ -0,0 +1,105 @@
+#!/usr/bin/env ruby
+
+$monkeys = {}
+
+class IsHuman < ::StandardError
+end
+
+class Monkey
+  def initialize(name, operation)
+    number_format = /^(?<num>[[:digit:]]+)$/
+    calc_format = /^(?<m1>[[:alpha:]]+) (?<op>[-+*\/=]) (?<m2>[[:alpha:]]+)$/
+
+    @operation = operation
+    @name = name
+    @value = nil
+
+    if m = number_format.match(@operation)
+      @value = m['num'].to_i
+    else
+      m = calc_format.match(@operation)
+      @m1 = m['m1']
+      @op = m['op']
+      @op = '==' if @name == 'root'
+      @m2 = m['m2']
+    end
+  end
+
+  def value
+    raise IsHuman if setting? and @name == 'humn'
+    return @value if @value
+
+    @value = $monkeys[@m1].value.send(@op, $monkeys[@m2].value)
+  end
+
+  def set_equal!(value)
+    if @name == 'humn'
+      @value = value
+      return
+    end
+
+    begin
+      left = $monkeys[@m1].value
+    rescue IsHuman
+      left = nil
+    end
+    begin
+      right = $monkeys[@m2].value
+    rescue IsHuman
+      right = nil
+    end
+
+    case @op
+    when '=='
+      $monkeys[@m1].set_equal!(right) if right
+      $monkeys[@m2].set_equal!(left) if left
+    when '+'
+      $monkeys[@m1].set_equal!(value - right) if right
+      $monkeys[@m2].set_equal!(value - left) if left
+    when '-'
+      $monkeys[@m1].set_equal!(value + right) if right
+      $monkeys[@m2].set_equal!(left - value) if left
+    when '*'
+      $monkeys[@m1].set_equal!(value / right) if right
+      $monkeys[@m2].set_equal!(value / left) if left
+    when '/'
+      $monkeys[@m1].set_equal!(value * right) if right
+      $monkeys[@m2].set_equal!(left / value) if left
+    end
+  end
+
+  def to_s
+    "<#{self.class}: #{@name} = #{@operation} (#{@value})>"
+  end
+
+  alias inspect to_s
+
+  def self.setting=(maybe)
+    @@setting = maybe
+  end
+
+  def self.setting
+    @@setting ||= false
+  end
+
+  private
+
+  def setting?
+    self.class.setting
+  end
+end
+
+
+input = File.read('21.input').lines
+
+monkey_format = /^(?<name>[[:alpha:]]+): (?<op>.*)$/
+
+input.each do |line|
+  m = monkey_format.match line
+  $monkeys[m['name']] = Monkey.new(m['name'], m['op'])
+end
+
+Monkey.setting = true
+$monkeys['root'].set_equal! nil
+Monkey.setting = false
+print $monkeys['humn'].value, "\n"