From: Greg Burri <greg.burri@gmail.com>
Date: Sun, 24 Dec 2017 13:06:31 +0000 (+0100)
Subject: Day 24
X-Git-Url: https://git.euphorik.ch/?a=commitdiff_plain;h=0b402a149cb4291e3c6cc6a4cdea2b2b2ea51456;p=advent_of_code_2017.git

Day 24
---

diff --git a/AdventOfCode2017.sln b/AdventOfCode2017.sln
index 9a4c28b..2c108a1 100644
--- a/AdventOfCode2017.sln
+++ b/AdventOfCode2017.sln
@@ -46,4 +46,7 @@ Global
 	GlobalSection(Performance) = preSolution
 		HasPerformanceSessions = true
 	EndGlobalSection
+	GlobalSection(Performance) = preSolution
+		HasPerformanceSessions = true
+	EndGlobalSection
 EndGlobal
diff --git a/AdventOfCode2017/AdventOfCode2017.fsproj b/AdventOfCode2017/AdventOfCode2017.fsproj
index 0faadbe..e568040 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>23</StartArguments>
+    <StartArguments>24</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>23</StartArguments>
+    <StartArguments>24</StartArguments>
   </PropertyGroup>
   <PropertyGroup>
     <MinimumVisualStudioVersion Condition="'$(MinimumVisualStudioVersion)' == ''">11</MinimumVisualStudioVersion>
@@ -82,6 +82,7 @@
     <Compile Include="Day21.fs" />
     <Compile Include="Day22.fs" />
     <Compile Include="Day23.fs" />
+    <Compile Include="Day24.fs" />
     <Compile Include="Program.fs" />
     <None Include="App.config" />
     <Content Include="Data\day01.input">
@@ -153,6 +154,9 @@
     <Content Include="Data\day23.input">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="Data\day24.input">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
diff --git a/AdventOfCode2017/Day23.fs b/AdventOfCode2017/Day23.fs
index 34cde9a..9b0556d 100644
--- a/AdventOfCode2017/Day23.fs
+++ b/AdventOfCode2017/Day23.fs
@@ -1,7 +1,5 @@
 module AdventOfCode2017.Day23
 
-open System
-
 type From =
     | FromReg of char
     | FromValue of int64
@@ -13,7 +11,7 @@ type Instruction =
     | Jump of From * From
 
 let parseInput (lines : string[]) : Instruction[] =
-    let readFrom (str : string) = if Char.IsLetter str.[0] then FromReg str.[0] else FromValue (int64 str)
+    let readFrom (str : string) = if System.Char.IsLetter str.[0] then FromReg str.[0] else FromValue (int64 str)
     lines
     |> Array.map (
         fun line ->
@@ -51,6 +49,7 @@ let debug () =
     while not ``end`` do
         let mutable f = 1
         let mutable d = 2
+
         let mutable loop = true
         while loop do
             f <- if b % d = 0 then 0 else f
@@ -61,7 +60,6 @@ let debug () =
             h <- h + 1
 
         ``end`` <- b = c
-
         b <- b + 17
     h
 
diff --git a/AdventOfCode2017/Day24.fs b/AdventOfCode2017/Day24.fs
new file mode 100644
index 0000000..84b3802
--- /dev/null
+++ b/AdventOfCode2017/Day24.fs
@@ -0,0 +1,36 @@
+module AdventOfCode2017.Day24
+
+type Components = (int * int) list
+
+let parseInput (lines : string[]) : Components =
+    lines
+    |> List.ofArray
+    |> List.map (
+        fun line ->
+            let numbers = line.Split '/'
+            int numbers.[0], int numbers.[1]
+    )
+
+let rec chooseAndRemove (f : 'a -> 'b option) (l : 'a list) : ('b * 'a list) list =
+    l
+    |> List.choose (fun e -> match f e with Some e' -> Some (e, e') | None -> None)
+    |> List.map (fun (e, e') -> e', l |> List.except [ e ])
+
+let bridges (components : Components) : Components list =
+    let rec build (components : Components) (bridge : Components) : Components list =
+        let validComponents =
+            components
+            |> chooseAndRemove
+                (match bridge with
+                | [] -> fun (a, b) -> if a = 0 then Some (b, a) else None
+                | (a, _) :: _ -> fun (a', b') -> if a' = a then Some (b', a') elif b' = a then Some (a', b') else None)
+
+        if List.isEmpty validComponents then
+            [ bridge ]
+        else
+            validComponents |> List.fold (fun bridges (c, cs) -> build cs (c :: bridge) @ bridges) []
+    build components []
+
+let bridgeValue = List.sumBy (fun (a, b) -> a + b)
+let maxBridge = List.map bridgeValue >> List.max
+let longestBridge = List.sortByDescending (fun bridge -> List.length bridge, bridgeValue bridge) >> List.head >> bridgeValue
diff --git a/AdventOfCode2017/Program.fs b/AdventOfCode2017/Program.fs
index 781fb24..65f1fbf 100644
--- a/AdventOfCode2017/Program.fs
+++ b/AdventOfCode2017/Program.fs
@@ -104,6 +104,11 @@ let day23 () =
     let input = File.ReadAllLines "Data/day23.input" |> Day23.parseInput
     sprintf "part1 = %A, part2 = %A" (Day23.run input) (Day23.debug ())
 
+let day24 () =
+    let input = File.ReadAllLines "Data/day24.input" |> Day24.parseInput
+    let bridges = Day24.bridges input
+    sprintf "part1 = %A, part2 = %A" (Day24.maxBridge bridges) (Day24.longestBridge bridges)
+
 let doDay (n : int) =
     let sw = Diagnostics.Stopwatch ()
     sw.Start ()
@@ -132,6 +137,7 @@ let doDay (n : int) =
         | 21 -> day21 ()
         | 22 -> day22 ()
         | 23 -> day23 ()
+        | 24 -> day24 ()
         | _ -> raise <| NotImplementedException ()
     printfn "Result of day %i: %s (time : %i ms)" n result sw.ElapsedMilliseconds
 
diff --git a/Tests/Day24 tests.fs b/Tests/Day24 tests.fs
new file mode 100644
index 0000000..eb78b76
--- /dev/null
+++ b/Tests/Day24 tests.fs	
@@ -0,0 +1,42 @@
+namespace AdventOfCode2017.Tests
+
+open System
+open Xunit
+open Xunit.Abstractions
+open Swensen.Unquote
+
+open AdventOfCode2017
+
+type ``Day24 tests`` (output : ITestOutputHelper) =
+
+    [<Fact>]
+    let ``(Part1) From web page`` () =
+        let input =
+            [|
+                "0/2"
+                "2/2"
+                "2/3"
+                "3/4"
+                "3/5"
+                "0/1"
+                "10/1"
+                "9/10"
+            |] |> Day24.parseInput
+        let bridges = Day24.bridges input
+        Day24.maxBridge bridges =! 31
+
+    [<Fact>]
+    let ``(Part2) From web page`` () =
+        let input =
+            [|
+                "0/2"
+                "2/2"
+                "2/3"
+                "3/4"
+                "3/5"
+                "0/1"
+                "10/1"
+                "9/10"
+            |] |> Day24.parseInput
+        let bridges = Day24.bridges input
+        Day24.longestBridge bridges =! 19
\ No newline at end of file
diff --git a/Tests/Tests.fsproj b/Tests/Tests.fsproj
index e48cd23..31314ef 100644
--- a/Tests/Tests.fsproj
+++ b/Tests/Tests.fsproj
@@ -77,6 +77,7 @@
     <Compile Include="Day20 tests.fs" />
     <Compile Include="Day21 tests.fs" />
     <Compile Include="Day22 tests.fs" />
+    <Compile Include="Day24 tests.fs" />
     <Content Include="App.config" />
     <Content Include="packages.config" />
   </ItemGroup>