Advent of Code 2023, December 6

AdventOfCode2023.12.06fsx

#time "on"

open System
open System.IO

let input =
    File.ReadAllLines(__SOURCE_DIRECTORY__ + "/../data/input06.txt")

let rec getWinningMoves time record_distance speed acc =
    if speed > time then
        acc
    else
        let distance = speed * (time - speed)
        if distance > record_distance then
            getWinningMoves time record_distance (speed+1L) (acc+1L)
        else
            getWinningMoves time record_distance (speed+1L) acc

// Part One
let races =
    input
    |> Array.map (fun str -> (str.Split ':' |> Array.last).Trim().Split ' ' 
                            |> Array.filter (not << String.IsNullOrWhiteSpace) 
                            |> Array.map Int64.Parse)
Array.zip races[0] races[1]
|> Array.map (fun (time, distance) -> getWinningMoves time distance 0L 0L)
|> Array.fold (fun v acc -> v * acc) 1L

// Part Two
let race =
    input
    |> Array.map (fun str -> (str.Split ':' |> Array.last).Trim())
    |> Array.map (fun str -> str |> Array.ofSeq |> Array.filter (fun c -> c <> ' '))
    |> Array.map (fun chars -> String(chars))
    |> Array.map Int64.Parse
getWinningMoves race[0] race[1] 0L 0L