From f6d103e37c377b411c25cdedfa6f9bcaa9521f7c Mon Sep 17 00:00:00 2001
From: Ummon <greg.burri@gmail.com>
Date: Tue, 5 Dec 2017 08:43:03 +0100
Subject: [PATCH] Day 5

---
 AdventOfCode2017/AdventOfCode2017.fsproj |  6 +++++-
 AdventOfCode2017/Day4.fs                 |  4 +++-
 AdventOfCode2017/Day5.fs                 | 19 +++++++++++++++++++
 AdventOfCode2017/Program.fs              |  5 +++++
 Tests/Day5 tests.fs                      | 17 +++++++++++++++++
 Tests/Tests.fsproj                       |  1 +
 6 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 AdventOfCode2017/Day5.fs
 create mode 100644 Tests/Day5 tests.fs

diff --git a/AdventOfCode2017/AdventOfCode2017.fsproj b/AdventOfCode2017/AdventOfCode2017.fsproj
index dac598e..5a9b3ef 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>4</StartArguments>
+    <StartArguments>5</StartArguments>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -60,6 +60,7 @@
     <Compile Include="Day2.fs" />
     <Compile Include="Day3.fs" />
     <Compile Include="Day4.fs" />
+    <Compile Include="Day5.fs" />
     <Compile Include="Program.fs" />
     <None Include="App.config" />
     <None Include="Data\day1.input">
@@ -71,6 +72,9 @@
     <None Include="Data\day4.input">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Include="Data\day5.input">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <Content Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
diff --git a/AdventOfCode2017/Day4.fs b/AdventOfCode2017/Day4.fs
index c71ec77..fdab92f 100644
--- a/AdventOfCode2017/Day4.fs
+++ b/AdventOfCode2017/Day4.fs
@@ -7,7 +7,9 @@ let forallDistinctPairs (f : string -> string -> bool) (pp : string) =
             for b in a + 1 .. words.Length - 1 -> f words.[a] words.[b]
     ] |> List.forall not
 
+let isAnagram w1 w2 = Seq.compareWith compare (Seq.sort w1) (Seq.sort w2) = 0
+
 let passphraseValid = forallDistinctPairs (=)
-let isAnagram w1 w2 = Seq.compareWith (compare) (Seq.sort w1) (Seq.sort w2) = 0
 let passphraseValidAnagram = forallDistinctPairs isAnagram
+
 let nbPassphrasesValid (f : string -> bool) = Seq.map f >> Seq.sumBy (fun v -> if v then 1 else 0)
\ No newline at end of file
diff --git a/AdventOfCode2017/Day5.fs b/AdventOfCode2017/Day5.fs
new file mode 100644
index 0000000..dea50e3
--- /dev/null
+++ b/AdventOfCode2017/Day5.fs
@@ -0,0 +1,19 @@
+module AdventOfCode2017.Day5
+
+open System
+
+let parseInput (str : string) : int[] =
+    str.Split ([| '\r'; '\t'; ' ' |], StringSplitOptions.RemoveEmptyEntries) |> Array.map int
+
+let nbSteps (next : int -> int) (instructions : int[])  =
+    let is = instructions.[*]
+    let mutable cursor, steps = 0, 0
+    while cursor >= 0 && cursor < instructions.Length do
+        let i = is.[cursor]
+        is.[cursor] <- next is.[cursor]
+        cursor <- cursor + i
+        steps <- steps + 1
+    steps
+
+let nbSteps1 = nbSteps ((+) 1)
+let nbSteps2 = nbSteps (fun i -> if i >= 3 then i - 1 else i + 1)
\ No newline at end of file
diff --git a/AdventOfCode2017/Program.fs b/AdventOfCode2017/Program.fs
index 52ac0e9..db1ca80 100644
--- a/AdventOfCode2017/Program.fs
+++ b/AdventOfCode2017/Program.fs
@@ -19,6 +19,10 @@ let day4 () =
     let input = File.ReadAllLines "Data/day4.input"
     sprintf "part1 = %A, part2 = %A" (Day4.nbPassphrasesValid Day4.passphraseValid input) (Day4.nbPassphrasesValid Day4.passphraseValidAnagram input)
 
+let day5 () =
+    let input = File.ReadAllText "Data/day5.input"
+    sprintf "part1 = %A, part2 = %A" (Day5.nbSteps1 (Day5.parseInput input)) (Day5.nbSteps2 (Day5.parseInput input))
+
 let doDay (n : int) =
     let result =
         match n with
@@ -26,6 +30,7 @@ let doDay (n : int) =
         | 2 -> day2 ()
         | 3 -> day3 ()
         | 4 -> day4 ()
+        | 5 -> day5 ()
         | _ -> raise <| NotImplementedException ()
     printfn "Result of day %i: %s" n result
 
diff --git a/Tests/Day5 tests.fs b/Tests/Day5 tests.fs
new file mode 100644
index 0000000..3ddf954
--- /dev/null
+++ b/Tests/Day5 tests.fs	
@@ -0,0 +1,17 @@
+namespace AdventOfCode2017.Tests
+
+open Xunit
+open Xunit.Abstractions
+open Swensen.Unquote
+
+open AdventOfCode2017
+
+type ``Day5 tests`` (output : ITestOutputHelper) =
+
+    [<Fact>]
+    let ``(Part1) From web page`` () =
+        Day5.nbSteps1 [| 0; 3; 0; 1; -3 |] =! 5
+
+    [<Fact>]
+    let ``(Part2) From web page`` () =
+        Day5.nbSteps2 [| 0; 3; 0; 1; -3 |] =! 10
\ No newline at end of file
diff --git a/Tests/Tests.fsproj b/Tests/Tests.fsproj
index 9721c8e..1b36559 100644
--- a/Tests/Tests.fsproj
+++ b/Tests/Tests.fsproj
@@ -59,6 +59,7 @@
     <Compile Include="Day2 tests.fs" />
     <Compile Include="Day3 tests.fs" />
     <Compile Include="Day4 tests.fs" />
+    <Compile Include="Day5 tests.fs" />
     <Content Include="packages.config" />
     <Content Include="App.config" />
   </ItemGroup>
-- 
2.45.2