artur-s

// Monadic DI: Reader and Free monad
// https://www.youtube.com/watch?v=ZasXwtTRkio


module Reader =

    type Reader<'d, 'a> = {Apply:('d -> 'a)}
    let reader f = {Reader.Apply = f}
    let (|Reader|) ({Reader.Apply = apply}) = apply

artur-s

// non-recursive implementation of Y-combinator, based on example from https://en.wikipedia.org/wiki/Fixed-point_combinator#Type_for_the_Y_combinator
// with memoization


using System;
using System.Diagnostics;
using System.Collections.Concurrent;


//type 'a Recc = In of ('a Recc -> 'a)

artur-s

let scanLeft (s:'s) (f:'s -> 'a -> 's) (lst:'a list) : 's list =
    lst 
    |> List.mapi (fun i _ ->
        lst
        |> List.take i
        |> List.fold f s )
        

artur-s

// https://adventofcode.com/2021

let readings =
    [|
        199
        227
        229 
    |]

// part1