Finish day 8

2 files changed, 67 insertions, 0 deletions

diff --git a/aoc-2022-dotnet/Day08/Day08.fsproj b/aoc-2022-dotnet/Day08/Day08.fsproj
new file mode 100644
index 0000000..e337a41
--- /dev/null
+++ b/aoc-2022-dotnet/Day08/Day08.fsproj
@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Content Include="test.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+    <Content Include="input.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+    <Compile Include="Program.fs" />
+  </ItemGroup>
+
+</Project>
diff --git a/aoc-2022-dotnet/Day08/Program.fs b/aoc-2022-dotnet/Day08/Program.fs
new file mode 100644
index 0000000..1a98c6d
--- /dev/null
+++ b/aoc-2022-dotnet/Day08/Program.fs
@@ -0,0 +1,49 @@
+module Day08
+
+open System.IO
+open System.Globalization
+
+let parseMatrix =
+    array2D
+    >> Array2D.map CharUnicodeInfo.GetDigitValue
+
+let mapEachToSeq mapping m =
+    seq {
+        for r in 0 .. Array2D.length1 m - 1 do
+            for c in 0 .. Array2D.length2 m - 1 -> mapping m r c
+    }
+
+let sideViews (m: 'a [,]) r c =
+    [ m[0 .. r - 1, c] |> Array.rev
+      m[r, c + 1 ..]
+      m[r + 1 .., c]
+      m[r, 0 .. c - 1] |> Array.rev ]
+
+let isVisible (m: 'a [,]) r c =
+    not
+    <| List.forall (Array.exists ((<=) m[r, c])) (sideViews m r c)
+
+let scenicScore (m: 'a [,]) r c =
+    sideViews m r c
+    |> List.map (fun s ->
+        s
+        |> Seq.tryFindIndex ((<=) m[r, c])
+        |> Option.map ((+) 1)
+        |> Option.defaultValue (Array.length s))
+    |> List.reduce (*)
+
+let solution1 =
+    parseMatrix
+    >> mapEachToSeq isVisible
+    >> Seq.filter id
+    >> Seq.length
+
+let solution2 = parseMatrix >> mapEachToSeq scenicScore >> Seq.max
+
+let test = File.ReadLines("test.txt")
+assert (solution1 test = 21)
+assert (solution2 test = 8)
+
+let input = File.ReadLines("input.txt")
+printfn "%d" <| solution1 input
+printfn "%d" <| solution2 input