AdventOfCode2025.Day01.fsx

AdventOfCode2025.Day01.fsx

#time "on"

open System
open System.IO

let input =
    File.ReadAllLines(__SOURCE_DIRECTORY__ + "/../data/input01.txt")
    |> Seq.toList


// Part One
input
|> List.fold (fun (sum, count) cmd -> 
    let steps = Int32.Parse (cmd.Substring 1)
    let sum = if cmd[0] = 'R' then sum + steps else sum - steps
    let count = if sum % 100 = 0 then count+1 else count
    sum % 100, count) (50, 0)

// Part Two
input
|> List.fold (fun (sum, count) cmd -> 
    let steps = Int32.Parse (cmd.Substring 1)
    let new_sum = ((if cmd[0] = 'R' then sum + steps else sum - steps) % 100 + 100) % 100
    let count = 
        (if cmd[0] = 'R' && new_sum < sum || cmd[0] = 'L' && (sum <> 0 && new_sum > sum || new_sum = 0) 
            then count + 1 
        else 
            count) 
        + steps / 100
    new_sum, count) (50, 0)