copy pasting the rules from last year’s thread:

Rules: no spoilers.

The other rules are made up aswe go along.

Share code by link to a forge, home page, pastebin (Eric Wastl has one here) or code section in a comment.

  • @ArchiteuthisOP
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    edit-2
    10 hours ago

    Got stuck forever on 2-2 because of an edge case that only showed up in 7/1000 reports, ended up just brute forcing it, just ran the fitness function after removing an element in sequence.

    Then solved 3.x in like minutes because I could be worse at regex, posting code mostly because no-one else posted F# yet.

    3-2 in F#

    spoiler
    "./input.actual"
    |> System.IO.File.ReadAllText
    |> fun source -> 
        System.Text.RegularExpressions.Regex.Matches(source, @"don't\(\)|do\(\)|mul\((\d+),(\d+)\)")
        |> Seq.fold
            (fun (acc, enabled) m ->
                match m.Value with
                | "don't()" -> acc, false
                | "do()" -> acc, true
                | mul when enabled && mul.StartsWith("mul") ->
                    let (x, y) = int m.Groups.[1].Value, int m.Groups.[2].Value
                    acc + x * y, enabled
                | _ -> acc, enabled ) 
            (0, true)
        |> fst
    |> printfn "The sum of all valid multiplications with respect to do() and don't() is %A"
    
    

    comments

    spoiler

    Not much to say, the regex grabs all relevant strings and the folding function propagates a flag that flips according to do/don’t and an accumulator that is increased when a mul() is encountered and parsed.