From 446af4ea857eebe0599fcb136bec6f7550350e99 Mon Sep 17 00:00:00 2001
From: Greg Burri <greg.burri@gmail.com>
Date: Fri, 22 Dec 2017 20:59:53 +0100
Subject: [PATCH] Day 21 (WIP)

---
 AdventOfCode2017/AdventOfCode2017.fsproj | 12 ++--
 AdventOfCode2017/Day21.fs                | 79 ++++++++++++++++++++++++
 AdventOfCode2017/packages.config         |  1 +
 Tests/Day21 tests.fs                     | 18 ++++++
 Tests/Tests.fsproj                       |  1 +
 5 files changed, 105 insertions(+), 6 deletions(-)
 create mode 100644 AdventOfCode2017/Day21.fs
 create mode 100644 Tests/Day21 tests.fs

diff --git a/AdventOfCode2017/AdventOfCode2017.fsproj b/AdventOfCode2017/AdventOfCode2017.fsproj
index 4cc42dc..6ff95f3 100644
--- a/AdventOfCode2017/AdventOfCode2017.fsproj
+++ b/AdventOfCode2017/AdventOfCode2017.fsproj
@@ -25,7 +25,7 @@
     <PlatformTarget>AnyCPU</PlatformTarget>
     <DocumentationFile>bin\$(Configuration)\$(AssemblyName).XML</DocumentationFile>
     <Prefer32Bit>true</Prefer32Bit>
-    <StartArguments>20</StartArguments>
+    <StartArguments>21</StartArguments>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -37,7 +37,7 @@
     <PlatformTarget>AnyCPU</PlatformTarget>
     <DocumentationFile>bin\$(Configuration)\$(AssemblyName).XML</DocumentationFile>
     <Prefer32Bit>true</Prefer32Bit>
-    <StartArguments>20</StartArguments>
+    <StartArguments>21</StartArguments>
   </PropertyGroup>
   <PropertyGroup>
     <MinimumVisualStudioVersion Condition="'$(MinimumVisualStudioVersion)' == ''">11</MinimumVisualStudioVersion>
@@ -79,6 +79,7 @@
     <Compile Include="Day18Part2.fs" />
     <Compile Include="Day19.fs" />
     <Compile Include="Day20.fs" />
+    <Compile Include="Day21.fs" />
     <Compile Include="Program.fs" />
     <None Include="App.config" />
     <Content Include="Data\day01.input">
@@ -141,15 +142,14 @@
     <Content Include="Data\day20.input">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <None Include="Data\day21.input" />
     <Content Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
-    <Reference Include="mscorlib" />
     <Reference Include="FSharp.Core">
-      <Name>FSharp.Core</Name>
-      <AssemblyName>FSharp.Core.dll</AssemblyName>
-      <HintPath>$(MSBuildProgramFiles32)\Reference Assemblies\Microsoft\FSharp\.NETFramework\v4.0\$(TargetFSharpCoreVersion)\FSharp.Core.dll</HintPath>
+      <HintPath>..\packages\FSharp.Core.4.2.3\lib\net45\FSharp.Core.dll</HintPath>
     </Reference>
+    <Reference Include="mscorlib" />
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Numerics" />
diff --git a/AdventOfCode2017/Day21.fs b/AdventOfCode2017/Day21.fs
new file mode 100644
index 0000000..ff0da05
--- /dev/null
+++ b/AdventOfCode2017/Day21.fs
@@ -0,0 +1,79 @@
+module AdventOfCode2017.Day21
+
+open System
+
+type M = bool[,]
+
+let parseInput (lines : string[]) : (M * M) list =
+    let readMat (str : string) =
+        str.Split '/' |> Array.map (Array.ofSeq >> Array.map ((=) '#')) |> array2D
+
+        (*
+
+        let l = str.Length
+        let m = Array2D.zeroCreate l l : M
+        let rows = str.Split '/'
+        for i = 0 to l - 1 do
+            for j = 0 to l - 1 do
+                m.[i, j] <- rows.[i].[j] = '#'
+        m*)
+
+
+    lines
+    |> List.ofArray
+    |> List.map (
+        fun line ->
+            let matPair = line.Split ([| "=>" |], StringSplitOptions.RemoveEmptyEntries)
+            readMat matPair.[0], readMat matPair.[1]
+    )
+
+let fractalArt (patterns : (M * M) list) : int =
+    let turn (m : M) =
+        let l = Array2D.length1 m
+        let m' = Array2D.zeroCreate l l
+        if Array2D.length1 m = 2 then
+            m'.[0,0] <- m.[1,0]
+            m'.[0,1] <- m.[0,0]
+            m'.[1,1] <- m.[0,1]
+            m'.[1,0] <- m.[1,1]
+        else
+            m'.[0,0] <- m.[2,0]
+            m'.[0,1] <- m.[1,0]
+            m'.[0,2] <- m.[0,0]
+            m'.[1,2] <- m.[0,1]
+            m'.[2,2] <- m.[0,2]
+            m'.[2,1] <- m.[1,2]
+            m'.[2,0] <- m.[2,2]
+            m'.[1,0] <- m.[2,1]
+        m'
+
+    let flip (m : M) =
+        let l = Array2D.length1 m
+        let m' = Array2D.zeroCreate l l
+        if Array2D.length1 m = 2 then
+            m'.[0,0] <- m.[0,1]
+            m'.[0,1] <- m.[0,0]
+            m'.[1,1] <- m.[1,0]
+            m'.[1,0] <- m.[1,1]
+        else
+            m'.[0,0] <- m.[0,2]
+            m'.[1,0] <- m.[1,2]
+            m'.[2,0] <- m.[2,2]
+            m'.[0,2] <- m.[0,0]
+            m'.[1,2] <- m.[1,0]
+            m'.[2,2] <- m.[2,0]
+        m'
+
+    let variants (m : M) : M list =
+        let l = List.unfold (fun (i, m) -> if i < 4 then Some (m, (i + 1, turn m)) else None) (0, m)
+        if Array2D.length1 m > 2 then l @ (l |> List.map flip) else l
+
+    let next (m : M) : M =
+        let l = Array2D.length1 m
+        if l % 2 = 0 then
+            let l' = l + l / 2
+        else
+
+    let mutable n = 0
+    next (array2 [ [ false; true; false ]; [ false; false; true ]; [ true; true; true] ]) |> Array2D.iter (fun e -> if e then n <- n + 1)
+    n
\ No newline at end of file
diff --git a/AdventOfCode2017/packages.config b/AdventOfCode2017/packages.config
index a90f359..42fe79c 100644
--- a/AdventOfCode2017/packages.config
+++ b/AdventOfCode2017/packages.config
@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="FSharp.Core" version="4.2.3" targetFramework="net462" />
   <package id="System.ValueTuple" version="4.4.0" targetFramework="net462" />
 </packages>
\ No newline at end of file
diff --git a/Tests/Day21 tests.fs b/Tests/Day21 tests.fs
new file mode 100644
index 0000000..c5677c5
--- /dev/null
+++ b/Tests/Day21 tests.fs	
@@ -0,0 +1,18 @@
+namespace AdventOfCode2017.Tests
+
+open System
+open Xunit
+open Xunit.Abstractions
+open Swensen.Unquote
+
+open AdventOfCode2017
+
+type ``Day21 tests`` (output : ITestOutputHelper) =
+
+    [<Fact>]
+    let ``(Part1) From web page`` () =
+            ()
+
+    [<Fact>]
+    let ``(Part2) From web page`` () =
+            ()
\ No newline at end of file
diff --git a/Tests/Tests.fsproj b/Tests/Tests.fsproj
index 1987918..4576901 100644
--- a/Tests/Tests.fsproj
+++ b/Tests/Tests.fsproj
@@ -75,6 +75,7 @@
     <Compile Include="Day18 tests.fs" />
     <Compile Include="Day19 tests.fs" />
     <Compile Include="Day20 tests.fs" />
+    <Compile Include="Day21 tests.fs" />
     <Content Include="App.config" />
     <Content Include="packages.config" />
   </ItemGroup>
-- 
2.45.2