68 lines
1.9 KiB
Forth
68 lines
1.9 KiB
Forth
namespace AdventOfCode2023
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open System
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open System.Collections.Generic
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open System.Globalization
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[<RequireQualifiedAccess>]
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module Day8 =
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type Instructions =
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{
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/// "true" is 'R'
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Steps : bool array
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Nodes : Dictionary<string, string * string>
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}
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let parse (s : string) =
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use mutable lines = StringSplitEnumerator.make '\n' s
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lines.MoveNext () |> ignore
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let stepsLine = lines.Current.TrimEnd()
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let steps = Array.zeroCreate stepsLine.Length
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for i = 0 to stepsLine.Length - 1 do
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steps.[i] <- (stepsLine.[i] = 'R')
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let dict = Dictionary ()
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while lines.MoveNext () do
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if not lines.Current.IsEmpty then
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use mutable line = StringSplitEnumerator.make' ' ' lines.Current
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line.MoveNext () |> ignore
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let key = line.Current.ToString ()
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line.MoveNext () |> ignore
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line.MoveNext () |> ignore
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let v1 = line.Current.Slice(1, line.Current.Length - 2).ToString ()
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line.MoveNext () |> ignore
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let v2 = line.Current.Slice(0, line.Current.Length - 1).ToString ()
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dict.[key] <- (v1, v2)
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{
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Steps = steps
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Nodes = dict
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}
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let part1 (s : string) =
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let data = parse s
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let mutable i = 0
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let mutable currentNode = "AAA"
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let mutable answer = 0
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while currentNode <> "ZZZ" do
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let instruction = data.Nodes.[currentNode]
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if data.Steps.[i] then
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// "true" is R
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currentNode <- snd instruction
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else
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currentNode <- fst instruction
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i <- (i + 1) % data.Steps.Length
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answer <- answer + 1
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answer
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let part2 (s : string) =
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let data = parse s
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let mutable answer = 0
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answer
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