math.randomseed(os.time())

deck = {}

function gen_deck()
	local deck = {}
	for i = 1, 20 do
		deck[i] = {I = i; T = '-'}
	end
	for i = 21, 60 do
		deck[i] = {I = i, T = 'O'}
	end
	return deck
end

function tcard(card)
	return card.T .. string.format(' ( %2.f )', card.I)
end

function print_deck(deck)
	for i = 1, 60 do
		print(tcard(deck[i]))
	end
end

function print_decks(deck, deck2)
	print("---")
	for i = 1, 60 do
		print(tcard(deck[i]), "\t", tcard(deck2[i]))
	end
end

function mash_deck(deck)
	-- New deck to move cards into
	local new_deck = {}

	-- The last card that we pick up
	local cut_index = math.random(22, 30)

	-- How many to leave undisturbed when moving the cut block over
	local undisturbed_count = math.random(3, 16)
	
	-- Start with the undistrubed cards
	for i = 1, undisturbed_count do
		new_deck[i] = deck[cut_index + i]
	end

	-- Now do the mash zone
	local insert_index = cut_index + undisturbed_count + 1
	local insert_size = 60 - undisturbed_count - cut_index
	local mashed_from_block = 0
	local mashed_from_insert = 0
	while true do
		-- Add a card from the block
		if mashed_from_block >= cut_index then break end
		mashed_from_block = mashed_from_block + 1
		local card_from_block = deck[mashed_from_block]
		table.insert(new_deck, card_from_block)

		-- Possibly, add another card from the block
		if math.random() < 1/10 then
			if mashed_from_block >= cut_index then break end
			mashed_from_block = mashed_from_block + 1
			local card_from_block = deck[mashed_from_block]
			table.insert(new_deck, card_from_block)
		end

		-- Add a card from the insert into
		if mashed_from_insert < insert_size then
			local card = deck[insert_index + mashed_from_insert]
			mashed_from_insert = mashed_from_insert + 1
			table.insert(new_deck, card)
		end

		-- Maybe add another card from the insert into
		if math.random() < 1/10 and mashed_from_insert < insert_size then
			local card = deck[insert_index + mashed_from_insert]
			mashed_from_insert = mashed_from_insert + 1
			table.insert(new_deck, card)
		end
	end

	-- Add any unused insert cards
	while mashed_from_insert < insert_size do
		local card = deck[insert_index + mashed_from_insert]
		mashed_from_insert = mashed_from_insert + 1
		table.insert(new_deck, card)
	end

	-- update deck
	return new_deck
end

function fischer_shuffle(deck)
	for i = 59, 0, -1 do
		local j = math.random(0, i)
		deck[j+1], deck[i+1] = deck[i+1], deck[j+1]
	end
	return deck
end

local deck1 = gen_deck()
for i = 1, 6 do
	deck1 = mash_deck(deck1)
end

local deck2 = gen_deck()
deck2 = fischer_shuffle(deck2)

--print_decks(deck1, deck2)

counts = {}
for i = 1, 60 do
	counts[i] = 0
end
local times = 60000
for i = 1, times do
	local deck = gen_deck()
	for i = 1, 5 do
		deck = mash_deck(deck)
	end
	counts[deck[1].I] = counts[deck[1].I] + 1
end
for i = 1, 60 do
	print(" "..string.format('%.2fx', counts[i]/(times/60)))
end

--[[
               cut_index
                  |      Cut Block
                  |.------^----.
       |||||||||||||||||||||||||
(Remaining cards) |

  (Cut Block)   undisturbed_count
||||||||||||||  |
         vvvv .-^-.
        |||||||||||
         (Remaining cards to mash into)

34, 7
24, 8
28, 17
27, 8
23, 17
25, 14

(22, 30), (3, 16)

]]

Timeout