aoc-2022-dotnet/Day01/Program.fs


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module Day01

open System.IO
open FSharpPlus

let parseLine =
    function
    | "" -> -1
    | l -> int l

let caloriesPerElf = Seq.split [ [ -1 ] ] >> Seq.map Seq.sum

let topN n xs =
    let rec insertSorted x =
        function
        | h :: t -> min h x :: (insertSorted (max h x) t)
        | _ -> [ x ]

    Seq.fold
        (fun acc x ->
            if List.length acc < n then
                insertSorted x acc
            elif List.head acc < x then
                insertSorted x <| List.tail acc
            else
                acc)
        List.empty
        xs

let solution n =
    Seq.map parseLine
    >> caloriesPerElf
    >> topN n
    >> List.sum

let test = File.ReadLines "test.txt"
assert (solution 1 test = 24000)
assert (solution 3 test = 45000)

let input = File.ReadLines "input.txt"
printfn "%d" <| solution 1 input
printfn "%d" <| solution 3 input