day14_part01.fs

module day14_part01

open System.Text.RegularExpressions

open AdventOfCode_2020.Modules
open System.Collections.Generic

type MaskGroup = {
    Mask: char array
    Memory: (int64*int64) list
}

let parseContent(input: string array) =
    let mutable idx = 0
    let mutable currentGroup = { Mask = [||]; Memory = [] }
    let mutable currentBlocks = []
    [
        while idx < input.Length do
            if input[idx].StartsWith("mask") then
                let mask = (input[idx].Split(" ")[2]).ToCharArray()
                if currentBlocks.Length = 0 then
                    currentGroup <- { currentGroup with Mask = mask }
                else
                    yield { currentGroup with Memory = currentBlocks }
                    currentGroup <- { currentGroup with Mask = mask }
                    currentBlocks <- []
            else
                let regexpattern = @"mem\[(\d+)] = (\d+)"
                let groups = Regex.Match(input[idx], regexpattern).Groups
                let (target, towrite) = ((int64)(groups[1].Value), (int64)(groups[2].Value))
                currentBlocks <- currentBlocks @ [(target, towrite)]
            idx <- idx + 1
        yield { currentGroup with Memory = currentBlocks }
    ]

let binarynumber (number: int64) =
    System.Convert.ToString(number, 2).PadLeft(36, '0').ToCharArray()

let runBlock(maskgroup: MaskGroup) (memory: Dictionary<int64, int64>) =
    maskgroup.Memory
    |> List.iter(fun (m, v) ->
        let value = binarynumber v
        let maskedv =
            String.concat "" ((Array.map2 (fun v1 v2 ->
                if v1 = 'X' then v2 else v1
            ) maskgroup.Mask value) |> Array.map string)
        let toinsert = System.Convert.ToInt64(maskedv, 2)
        if memory.ContainsKey(m) then
            memory[m] <- toinsert
        else
            memory.Add(m, toinsert)
    )
   
let memorzyValue (maskgroups: MaskGroup list) =
    let memory = Dictionary<int64, int64>()
    maskgroups |> List.iter(fun m ->  runBlock m memory)
    memory.Values |> Seq.sum

let execute =
    let path = "day14/day14_input.txt"
    let content = LocalHelper.GetLinesFromFile(path)
    let maskgroups = parseContent content

    memorzyValue maskgroups