theburningmonk

let part2 = 
  travel (1, 1)
  |> Seq.take 50
  |> Seq.map snd
  |> Seq.sumBy Seq.length
  |> (+) 1 // the starting position

theburningmonk

let part1 = 
  travel (1, 1)
  |> Seq.filter (fun (_, ps) -> ps |> List.exists ((=) (31, 39)))
  |> Seq.head
  |> fst

theburningmonk

#time

open System.Collections.Generic
open Checked

let input = 1362

// taken from http://www.necessaryandsufficient.net/2009/04/optimising-bit-counting-using-iterative-data-driven-development/
let countSetBits n =
  let n = n - ((n >>> 1) &&& 0x55555555)

theburningmonk

#time

open System.Collections.Generic
open Checked

let input = 1362

// taken from http://www.necessaryandsufficient.net/2009/04/optimising-bit-counting-using-iterative-data-driven-development/
let countSetBits n =
  let n = n - ((n >>> 1) &&& 0x55555555)

theburningmonk

let countSetBitsV1 n = 
  let rec loop n count =
    if n = 0 then count 
    else loop (n >>> 1) <| count + (n &&& 1)

  loop n 0

let countSetBitsV2 n =
  let rec loop n count =
    if n = 0 then count

theburningmonk

open System
open System.IO

let inputs = File.ReadAllLines (__SOURCE_DIRECTORY__ + "/Day12Input.txt")

let (|Int|_|) x = 
  match Int32.TryParse x with
  | true, n -> Some n
  | _       -> None

theburningmonk

let initFloorsPart2 =
  [| 
    set [ Generator "promethium"; Microchip "promethium"; 
          Generator "elerium";    Microchip "elerium";
          Generator "dilithium";  Microchip "dilithium" ]
    set [ Generator "cobalt"; Generator "curium"; 
          Generator "ruthenium"; Generator "plutonium" ]
    set [ Microchip "cobalt"; Microchip "curium"; 
          Microchip "ruthenium"; Microchip "plutonium" ]
    set []

theburningmonk

let initFloorsPart1 = 
  [| 
    set [ Generator "promethium"; Microchip "promethium" ]
    set [ Generator "cobalt"; Generator "curium"; 
          Generator "ruthenium"; Generator "plutonium" ]
    set [ Microchip "cobalt"; Microchip "curium"; 
          Microchip "ruthenium"; Microchip "plutonium" ]
    set []
  |]

theburningmonk

let solve initState =
  let visitedStates = new System.Collections.Generic.HashSet<string>()

  let next { Elevator = floorNum; Floors = floors } =
    // all the different ways items can be loaded into the elevator
    let itemCombos (floor : Floor) =
      seq {
        for item in floor do
          yield set [ item ]
          for otherItem in floor.Remove item do

theburningmonk

type State =
  {
    Elevator : int
    Floors   : Floor[]
  }

  override x.ToString() =
    let byElement = 
      x.Floors 
      |> Seq.mapi (fun n items -> items |> Seq.map (fun i -> n, i))