maze_generation_tail.ml

let rec combinations_tail f k m prefix  = match k, m with
    | a, b when a < 0 || b < 0 -> failwith "ki or mi negative"
    | a, b when a > b -> failwith "k > m"
    | 0, 0 -> if f (Array.of_list prefix) then [prefix] else []
    | 0, b -> combinations_tail f 0 (b-1) (false::prefix)
    | a, b when a = b -> combinations_tail f (a-1) (b-1) (true::prefix)
    | a, b ->  (combinations_tail f (a-1) (b-1) (true::prefix)) @ (combinations_tail f a (b-1) (false::prefix))
;;

let generate_tail m n = 
    combinations_tail (sanity_check m n) ((m-1) * (n-1)) (m*(n-1)+n*(m-1)) []
;;