Calculate probability that a hand of cards is dealt shuffled

errbuddy_shufflin.rb

class Dealer
	def initialize
		@deck = new_deck
	end

	def deal(size)
		if @deck.size < size
			@deck = new_deck
		end
		@deck.pop(size)
	end

	def new_deck
		((1..13).to_a * 4).shuffle
	end
end

class Array
	def in_order?
		current = 0
		each do |card|
			if card < current
				return false
			end
			current = card
		end
		return true
	end
end

hand_size = 10
trial_count = 1_000_000
wins = 0

dealer = Dealer.new

trial_count.times do
	hand = dealer.deal(hand_size)
	if hand.in_order?
		wins += 1
	end
end

puts "#{wins} shuffled out of #{trial_count} trials"
puts "#{(wins * 1.0 / trial_count * 100).round(6)}% success rate"