From 220274d5d3e5c9534de2322cc8158a040d994246 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Gergely?= <ggergely@kodfodrasz.net>
Date: Sun, 29 Dec 2024 23:54:30 +0100
Subject: [PATCH] Day 7 Part 1

---
 Kodfodrasz.AoC.Year2024.Tests/Day7Tests.fs    | 95 +++++++++++++++++++
 .../Kodfodrasz.AoC.Year2024.Tests.fsproj      |  1 +
 Kodfodrasz.AoC.Year2024/Day7.fs               | 75 +++++++++++++++
 .../Kodfodrasz.AoC.Year2024.fsproj            |  1 +
 4 files changed, 172 insertions(+)
 create mode 100644 Kodfodrasz.AoC.Year2024.Tests/Day7Tests.fs
 create mode 100644 Kodfodrasz.AoC.Year2024/Day7.fs

diff --git a/Kodfodrasz.AoC.Year2024.Tests/Day7Tests.fs b/Kodfodrasz.AoC.Year2024.Tests/Day7Tests.fs
new file mode 100644
index 0000000..35f2908
--- /dev/null
+++ b/Kodfodrasz.AoC.Year2024.Tests/Day7Tests.fs
@@ -0,0 +1,95 @@
+module Kodfodrasz.AoC.Year2024.Tests.Day7Tests
+
+open Xunit
+open Swensen.Unquote.Assertions
+
+open Kodfodrasz.AoC
+open Kodfodrasz.AoC.Year2024
+open Kodfodrasz.AoC.Year2024.Day7
+
+
+let exampleInput = """
+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20
+  """
+
+[<Fact>]
+let ``Parsing example input`` () =
+  let expected = [ 
+    {
+      TestValue = 190L
+      Terms = [10L; 19L]
+    }
+    {
+      TestValue = 3267L
+      Terms = [81L; 40L; 27L]
+    }
+    {
+      TestValue = 83L
+      Terms = [17L; 5L]
+    }
+    {
+      TestValue = 156L
+      Terms = [15L; 6L]
+    }
+    {
+      TestValue = 7290L
+      Terms = [6L; 8L; 6L; 15L]
+    }
+    {
+      TestValue = 161011L
+      Terms = [16L; 10L; 13L]
+    }
+    {
+      TestValue = 192L
+      Terms = [17L; 8L; 14L]
+    }
+    {
+      TestValue = 21037L
+      Terms = [9L; 7L; 18L; 13L]
+    }
+    {
+      TestValue = 292L
+      Terms = [11L; 6L; 16L; 20L]
+    }
+  ]
+
+  test
+    <@ let actual = parseInput exampleInput
+       actual = Ok expected @>
+
+[<Fact>]
+let ``Answer 1 helper function: check`` () =
+  let input = parseInput exampleInput |> Result.get
+
+  test <@ true = Day7.check input[0] @>
+  test <@ true = Day7.check input[1] @>
+  test <@ false = Day7.check input[3] @>
+  test <@ false = Day7.check input[5] @>
+  test <@ true = Day7.check input[8] @>
+
+
+[<Fact>]
+let ``Answer 1 for example input`` () =
+  let input = parseInput exampleInput
+
+  test
+    <@ let actual = Result.bind answer1 input
+       let expected: Result<_, string> = Ok 3749L
+       actual = expected @>
+
+[<Fact(Skip="TODO")>]
+let ``Answer 2 for example input`` () =
+  let input = parseInput exampleInput
+
+  test
+    <@ let actual = Result.bind answer2 input
+       let expected: Result<_, string> = Ok 31
+       actual = expected @>
diff --git a/Kodfodrasz.AoC.Year2024.Tests/Kodfodrasz.AoC.Year2024.Tests.fsproj b/Kodfodrasz.AoC.Year2024.Tests/Kodfodrasz.AoC.Year2024.Tests.fsproj
index 6497011..5785713 100644
--- a/Kodfodrasz.AoC.Year2024.Tests/Kodfodrasz.AoC.Year2024.Tests.fsproj
+++ b/Kodfodrasz.AoC.Year2024.Tests/Kodfodrasz.AoC.Year2024.Tests.fsproj
@@ -11,6 +11,7 @@
     <Compile Include="Day3Tests.fs" />
     <Compile Include="Day4Tests.fs" />
     <Compile Include="Day5Tests.fs" />
+    <Compile Include="Day7Tests.fs" />
     <Compile Include="Day11Tests.fs" />
     <Compile Include="Day13Tests.fs" />
     <Compile Include="Day20Tests.fs" />
diff --git a/Kodfodrasz.AoC.Year2024/Day7.fs b/Kodfodrasz.AoC.Year2024/Day7.fs
new file mode 100644
index 0000000..87621b7
--- /dev/null
+++ b/Kodfodrasz.AoC.Year2024/Day7.fs
@@ -0,0 +1,75 @@
+module Kodfodrasz.AoC.Year2024.Day7
+
+open System
+open System.Text.RegularExpressions
+open Kodfodrasz.AoC
+
+type CalibrationEquation = {
+  TestValue : int64
+  Terms: int64 list
+}
+
+type parsedInput = CalibrationEquation list
+let parseInput (input: string): Result<parsedInput,string> = 
+  let matchesEquatons= Regex.Matches(
+    input,
+    @"^\s*(?<testvalue>\d+):(?:\s+(?<n>\d+))+\s*$",
+    RegexOptions.Multiline)
+
+  let matchedEquations = 
+    let parseRule (m:Match) = 
+      let tv = m.Groups["testvalue"].Value |> int64
+      let terms = 
+        m.Groups["n"].Captures 
+        |> Seq.map (fun (c:Capture) -> c.Value |> int64)
+        |> Seq.toList
+
+      {
+        TestValue = tv
+        Terms = terms
+      }
+
+    matchesEquatons
+    |> Seq.map parseRule
+    |> Seq.toList
+  
+  Ok matchedEquations
+
+let check (eqn : CalibrationEquation) = 
+  let rec check goal acc terms = 
+    match terms with
+    | [] -> goal = acc
+    | head :: tail ->
+      if acc > goal then false
+      else 
+        if (check goal (acc + head) tail) then
+          true
+        else
+          check goal (acc * head) tail
+  match eqn.Terms with
+  | [] -> false
+  | h :: t -> check eqn.TestValue h t
+
+let answer1 (data : parsedInput) =
+  data
+  |> List.toArray
+  |> Array.Parallel.filter check
+  |> Array.sumBy(fun eqn -> eqn.TestValue)
+  |> Ok 
+
+let answer2 (data : parsedInput) =
+  failwith "TODO"
+
+type Solver() =
+  inherit SolverBase("Bridge Repair")
+  with
+    override this.Solve input =
+      input
+      |>
+      this.DoSolve
+        (parseInput)
+        [ 
+          answer1;
+          answer2;
+        ]
+
diff --git a/Kodfodrasz.AoC.Year2024/Kodfodrasz.AoC.Year2024.fsproj b/Kodfodrasz.AoC.Year2024/Kodfodrasz.AoC.Year2024.fsproj
index 28ce3e8..f7c45ed 100644
--- a/Kodfodrasz.AoC.Year2024/Kodfodrasz.AoC.Year2024.fsproj
+++ b/Kodfodrasz.AoC.Year2024/Kodfodrasz.AoC.Year2024.fsproj
@@ -11,6 +11,7 @@
     <Compile Include="Day3.fs" />
     <Compile Include="Day4.fs" />
     <Compile Include="Day5.fs" />
+    <Compile Include="Day7.fs" />
     <Compile Include="Day11.fs" />
     <Compile Include="Day13.fs" />
     <Compile Include="Day20.fs" />