Topswops

editable example

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ghul

use IO.Std.write_line

use Collections

swaps(deck: int[]) -> int => (

let cards = LIST()

for card in deck do

cards.add(card)

let count mut = 0

while cards[0] != 1 do

let top_card = cards[0]

let last = top_card - 1

for i in 0::(top_card - 1) / 2 do

let held = cards[i]

cards[i] = cards[last - i]

cards[last - i] = held

count = count + 1

count

)

topswops(n: int) -> int => (

let deck = LIST()

for card in 1::n do

deck.add(card)

let best mut = 0

let search = (position: int) -> void rec is

if position == n then

let rounds = swaps(deck.to_array())

if rounds > best then

best = rounds

else

for i in position::(n - 1) do

let held = deck[position]

deck[position] = deck[i]

deck[i] = held

rec(position + 1)

let put_back = deck[position]

deck[position] = deck[i]

deck[i] = put_back

search(0)

best

)

for n in 1::10 do

write_line("{n}: {topswops(n)}")

Topswops ​