f#exam

//Стуктура дерева арифметического выражения

type 't Node =
    |Mult of 't Node * 't Node
    |Plus of 't Node * 't Node
    |Sub of 't Node * 't Node
    |Div of 't Node * 't Node
    |Num of 't

type 't Tree =
    |Nil
    |Node of 't Node * 't Tree * 't Tree


//Максимум арифметического выражения (хуйня какая-то, но зашло)
let findMax lst =
    let rec findMax' acc fl lst =
        match lst with
        |[] -> if fl then 0 else acc
        |h::1::t when h > 0 -> findMax' (acc * (1+h)) false t
        |h::1::t when h < 0 -> findMax' (acc * (1-h)) false t
        |h::-1::t when h > 0 -> findMax' (acc * (1+h)) false t
        |h::-1::t when h < 0 -> findMax' (acc * (1-h)) false t
        |1::h::t when h > 0 -> findMax' (acc * (1+h)) false t
        |1::h::t when h < 0 -> findMax' (acc * (1-h)) false t
        |(-1)::h::t when h > 0 -> findMax' (acc * (1+h)) false t
        |(-1)::h::t when h < 0 -> findMax' (acc * (1-h)) false t
        |h::t when h > 0 -> findMax' (acc * h) false t
        |h::t when h < 0 -> findMax' (acc * -h) false t
        |h::t when h = 0 -> findMax' acc fl t
    findMax' 1 true lst

findMax [1;2;3]

// Деление массива на всевозможные 2 части (не сохраняет порядок, т.е. в массиве [1;2;3] есть вариант деления [2], [1;3])
let rec Division (lst : int list): ((int list) * (int list)) list =
    let rec MyMap acc lst k =
        match lst with
        |[] -> List.rev(acc)
        |h::t -> MyMap ((k::(fst h), snd h) :: (fst h, k::(snd h)) :: acc) t k

    match lst with
    |[] -> []
    |l when List.length(l) = 1 -> [([], [l.Head]); ([l.Head], [])]
    |h::t ->
        let subDiv = Division t
        MyMap [] subDiv h

Division [1;2;3;4]