From e664f2f9c3b2ef0034d94baa32e04e1e99665353 Mon Sep 17 00:00:00 2001
From: Ummon <greg.burri@gmail.com>
Date: Thu, 14 Dec 2017 09:41:42 +0100
Subject: [PATCH] Day 14

---
 AdventOfCode2017/AdventOfCode2017.fsproj |  3 ++-
 AdventOfCode2017/Day10.fs                |  6 +++--
 AdventOfCode2017/Day14.fs                | 32 ++++++++++++++++++++++++
 AdventOfCode2017/Program.fs              |  6 +++++
 Tests/Day14 tests.fs                     | 17 +++++++++++++
 Tests/Tests.fsproj                       |  1 +
 6 files changed, 62 insertions(+), 3 deletions(-)
 create mode 100644 AdventOfCode2017/Day14.fs
 create mode 100644 Tests/Day14 tests.fs

diff --git a/AdventOfCode2017/AdventOfCode2017.fsproj b/AdventOfCode2017/AdventOfCode2017.fsproj
index 074c067..34965a5 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>13</StartArguments>
+    <StartArguments>14</StartArguments>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -69,6 +69,7 @@
     <Compile Include="Day11.fs" />
     <Compile Include="Day12.fs" />
     <Compile Include="Day13.fs" />
+    <Compile Include="Day14.fs" />
     <Compile Include="Program.fs" />
     <None Include="App.config" />
     <Content Include="Data\day1.input">
diff --git a/AdventOfCode2017/Day10.fs b/AdventOfCode2017/Day10.fs
index a5cdb5d..ec3a4f1 100644
--- a/AdventOfCode2017/Day10.fs
+++ b/AdventOfCode2017/Day10.fs
@@ -21,5 +21,7 @@ let knotHash (nbRounds : int) (reduce : int[] -> string) (lengths : int list) (s
 let knotHash1 (str : string) =
     knotHash 1 (fun s -> s.[0] * s.[1] |> string) (str.Split ',' |> List.ofArray |> List.map int)
 
-let knotHash2 (str : string) =
-    knotHash 64 (Array.chunkBySize 16 >> Array.map (Array.reduce (^^^) >> sprintf "%02x") >> Array.reduce (+)) (List.append (str |> List.ofSeq |> List.map int) [ 17; 31; 73; 47; 23 ]) 256
\ No newline at end of file
+let knotHash2Encoding (encoding : int -> string) (str : string) =
+    knotHash 64 (Array.chunkBySize 16 >> Array.map (Array.reduce (^^^) >> encoding) >> Array.reduce (+)) (List.append (str |> List.ofSeq |> List.map int) [ 17; 31; 73; 47; 23 ]) 256
+
+let knotHash2 = knotHash2Encoding (sprintf "%02x")
\ No newline at end of file
diff --git a/AdventOfCode2017/Day14.fs b/AdventOfCode2017/Day14.fs
new file mode 100644
index 0000000..76bf281
--- /dev/null
+++ b/AdventOfCode2017/Day14.fs
@@ -0,0 +1,32 @@
+module AdventOfCode2017.Day14
+
+open System
+
+let hash = Day10.knotHash2Encoding (fun i -> Convert.ToString(i, 2).PadLeft(8, '0'))
+
+let buildMatrix (input : string) : bool[,] =
+    let mat = Array2D.zeroCreate 128 128
+    for i = 0 to 127 do
+        input + "-" + (string i) |> hash |> Seq.iteri (fun j c -> if c = '1' then mat.[i, j] <- true)
+    mat
+
+let nbOfUsedSquares (input : string) =
+    let mutable i = 0
+    buildMatrix input |> Array2D.iter (fun b -> if b then i <- i + 1)
+    i
+
+let nbOfConnectedRegions (input : string) =
+    let m = buildMatrix input
+
+    let rec remove i j =
+        if i >= 0 && i < 128 && j >= 0 && j < 128 && m.[i, j] then
+            m.[i, j] <- false
+            remove (i + 1) j |> ignore
+            remove (i - 1) j |> ignore
+            remove i (j + 1) |> ignore
+            remove i (j - 1) |> ignore
+            1
+        else
+            0
+
+    seq { for i in 0 .. 127 do for j in 0 .. 127 -> remove i j } |> Seq.sum
\ No newline at end of file
diff --git a/AdventOfCode2017/Program.fs b/AdventOfCode2017/Program.fs
index 0d32674..0c14451 100644
--- a/AdventOfCode2017/Program.fs
+++ b/AdventOfCode2017/Program.fs
@@ -62,6 +62,11 @@ let day13 () =
     let part1, part2 = Day13.severity input
     sprintf "part1 = %A, part2 = %A" part1 part2
 
+let day14 () =
+    let part1 = Day14.nbOfUsedSquares "hwlqcszp"
+    let part2 = Day14.nbOfConnectedRegions "hwlqcszp"
+    sprintf "part1 = %A, part2 = %A" part1 part2
+
 let doDay (n : int) =
     let sw = Diagnostics.Stopwatch ()
     sw.Start ()
@@ -80,6 +85,7 @@ let doDay (n : int) =
         | 11 -> day11 ()
         | 12 -> day12 ()
         | 13 -> day13 ()
+        | 14 -> day14 ()
         | _ -> raise <| NotImplementedException ()
     printfn "Result of day %i: %s (time : %i ms)" n result sw.ElapsedMilliseconds
 
diff --git a/Tests/Day14 tests.fs b/Tests/Day14 tests.fs
new file mode 100644
index 0000000..d8af382
--- /dev/null
+++ b/Tests/Day14 tests.fs	
@@ -0,0 +1,17 @@
+namespace AdventOfCode2017.Tests
+
+open Xunit
+open Xunit.Abstractions
+open Swensen.Unquote
+
+open AdventOfCode2017
+
+type ``Day14 tests`` (output : ITestOutputHelper) =
+
+    [<Fact>]
+    let ``(Part1) From web page`` () =
+        Day14.nbOfUsedSquares "flqrgnkx" =! 8108
+
+    [<Fact>]
+    let ``(Part2) From web page`` () =
+        Day14.nbOfConnectedRegions "flqrgnkx" =! 1242
\ No newline at end of file
diff --git a/Tests/Tests.fsproj b/Tests/Tests.fsproj
index 22aeb3a..3b76237 100644
--- a/Tests/Tests.fsproj
+++ b/Tests/Tests.fsproj
@@ -68,6 +68,7 @@
     <Compile Include="Day11 tests.fs" />
     <Compile Include="Day12 tests.fs" />
     <Compile Include="Day13 tests.fs" />
+    <Compile Include="Day14 tests.fs" />
     <Content Include="packages.config" />
     <Content Include="App.config" />
   </ItemGroup>
-- 
2.45.2