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open System | |
open System.IO | |
let readInts (path:string) : int [] = | |
use sw = new StreamReader (path) | |
sw.ReadToEnd().Split(",") | |
|> Array.map Int32.Parse | |
type Status = {memory:int[]; position: int; finished: bool;} | |
type Cmd = {opcode: int; op1:int ; op2: int; dest:int} | |
let runCmd (cmd:Cmd) (before: Status) : Status = | |
let updated = | |
before.memory | |
|> Array.mapi(fun pos value -> | |
if pos = cmd.dest then | |
(match cmd.opcode with | |
| 1 -> (+) | |
| 2 -> (*) | |
| _ -> failwith "wrong position") | |
before.memory.[cmd.op1] | |
before.memory.[cmd.op2] | |
else value | |
) | |
{memory = updated; position = before.position + 4; finished = updated.[before.position + 4] = 99} | |
let scenario (input: int[]) (noun:int) (verb:int) = | |
let resetMemory = | |
input | |
|> Array.mapi (fun pos value -> | |
match pos with | |
| 1 -> noun | |
| 2 -> verb | |
| _ -> value | |
) | |
let start = {memory = resetMemory; position = 0; finished = false} | |
Seq.unfold | |
(fun state -> | |
match state.finished with | |
| true -> None | |
| false -> | |
let cmd = | |
{ | |
opcode = state.memory.[state.position] | |
op1 = state.memory.[state.position + 1] | |
op2 = state.memory.[state.position + 2] | |
dest = state.memory.[state.position + 3] | |
} | |
let updated = runCmd cmd state | |
Some (updated.memory.[0], updated) | |
) start | |
|> Seq.last | |
[<EntryPoint>] | |
let main _ = | |
let timer = new Stopwatch() | |
timer.Start() | |
let input = readInts @"C:\dev\FSharp\AdventOfCode\Day2\input.txt" | |
//let noun = 12 | |
//let verb = 2 | |
for noun in [0..99] do | |
for verb in [0..99] do | |
let result = scenario input noun verb | |
if result = 19690720 then | |
//result.memory | |
//|> Array.iter (printfn "%d") | |
printfn "The answer is: %d" (100 * noun + verb) // 5936 | |
timer.Stop() | |
printfn "done in (%d) ms !" timer.ElapsedMilliseconds // done in (475) ms ! | |
Console.ReadKey() |> ignore | |
0 |
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