Dead

AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/AdventOfCode2023.FSharp.Lib.fsproj

@@ -13,6 +13,7 @@
     <Compile Include="Arithmetic.fs"/>
     <Compile Include="Rational.fs"/>
     <Compile Include="IntervalSet.fs" />
+    <Compile Include="List.fs" />
     <Compile Include="Day1.fs"/>
     <Compile Include="Day2.fs"/>
     <Compile Include="Day3.fs"/>

AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day19.fs

@@ -55,7 +55,8 @@ module Day19 =
                 | '<' -> true
                 | c -> failwith $"Bad comparison: %c{c}"
 
-            let operand = Int32.Parse (s.Slice (2, colon - 2), NumberStyles.None)
+            let operand =
+                Int32.Parse (s.Slice (2, colon - 2), NumberStyles.None, NumberFormatInfo.InvariantInfo)
 
             {
                 Component = comp
@@ -89,7 +90,7 @@ module Day19 =
                 None
         | _ -> failwith "bad component"
 
-    let rec compute (components : Dictionary<string, Rule ResizeArray * Dest>) x m a s (reg : string) =
+    let rec computePart1 (components : Dictionary<string, Rule ResizeArray * Dest>) x m a s (reg : string) =
         match components.TryGetValue reg with
         | false, _ -> failwith $"no rule matched: %s{reg}"
         | true, (rules, dest) ->
@@ -106,7 +107,7 @@ module Day19 =
                 | None -> i <- i + 1
 
             match result.Value with
-            | Register reg -> compute components x m a s reg
+            | Register reg -> computePart1 components x m a s reg
             | Accept -> true
             | Reject -> false
 
@@ -139,7 +140,8 @@ module Day19 =
                 let mutable s = 0
 
                 for comp in StringSplitEnumerator.make' ',' (row.Slice (1, row.Length - 2)) do
-                    let number = Int32.Parse (comp.Slice 2, NumberStyles.None)
+                    let number =
+                        Int32.Parse (comp.Slice 2, NumberStyles.None, NumberFormatInfo.InvariantInfo)
 
                     match comp.[0] with
                     | 'x' -> x <- number
@@ -148,7 +150,7 @@ module Day19 =
                     | 's' -> s <- number
                     | c -> failwith $"Bad char: %c{c}"
 
-                if compute workflows x m a s "in" then
+                if computePart1 workflows x m a s "in" then
                     answer <- answer + x + m + a + s
 
         answer
@@ -178,34 +180,134 @@ module Day19 =
         | _, AcceptanceCriterion.True -> AcceptanceCriterion.True
         | _, _ -> AcceptanceCriterion.Or (a, b)
 
-    let rec cata<'ret>
-        (atOr : 'ret -> 'ret -> 'ret)
-        (atAnd : 'ret -> 'ret -> 'ret)
-        (atFalse : unit -> 'ret)
-        (atTrue : unit -> 'ret)
-        (atBase : Component -> int -> int -> 'ret)
-        (ac : AcceptanceCriterion)
-        : 'ret
-        =
+    /// "low > high" means "empty interval"
+    [<Struct>]
+    type Interval =
+        {
+            Low : int
+            High : int
+        }
+
+        static member Empty =
+            {
+                Low = 1
+                High = 0
+            }
+
+    [<RequireQualifiedAccess>]
+    module Interval =
+        let size (i : Interval) =
+            if i.Low > i.High then 0 else i.High - i.Low + 1
+
+        let intersect (i1 : Interval) (i2 : Interval) =
+            if i1.Low > i1.High || i2.Low > i2.High then
+                i1
+            else if i1.High < i2.Low then
+                Interval.Empty
+            elif i2.High < i1.Low then
+                Interval.Empty
+            else
+                {
+                    Low = max i1.Low i2.Low
+                    High = min i1.High i2.High
+                }
+
+    type Conjunction =
+        {
+            X : Interval
+            M : Interval
+            A : Interval
+            S : Interval
+        }
+
+        static member All =
+            {
+                X =
+                    {
+                        Low = 1
+                        High = 4000
+                    }
+                M =
+                    {
+                        Low = 1
+                        High = 4000
+                    }
+                A =
+                    {
+                        Low = 1
+                        High = 4000
+                    }
+                S =
+                    {
+                        Low = 1
+                        High = 4000
+                    }
+            }
+
+    [<RequireQualifiedAccess>]
+    module Conjunction =
+        let conjAnd (c1 : Conjunction) (c2 : Conjunction) =
+            {
+                X = Interval.intersect c1.X c2.X
+                M = Interval.intersect c1.M c2.M
+                A = Interval.intersect c1.A c2.A
+                S = Interval.intersect c1.S c2.S
+            }
+
+        /// We rely on the intervals being disjoint by construction.
+        let size (x : Conjunction) : uint64 =
+            uint64 (Interval.size x.X)
+            * uint64 (Interval.size x.M)
+            * uint64 (Interval.size x.A)
+            * uint64 (Interval.size x.S)
+
+    type UnionOfConjunctions = Conjunction list
+
+    let rec toUnion (ac : AcceptanceCriterion) : UnionOfConjunctions =
         match ac with
-        | AcceptanceCriterion.False -> atFalse ()
-        | AcceptanceCriterion.True -> atTrue ()
-        | AcceptanceCriterion.Base (comp, low, high) -> atBase comp low high
-        | AcceptanceCriterion.And (a1, a2) ->
-            atAnd (cata atOr atAnd atFalse atTrue atBase a1) (cata atOr atAnd atFalse atTrue atBase a2)
-        | AcceptanceCriterion.Or (a1, a2) ->
-            atOr (cata atOr atAnd atFalse atTrue atBase a1) (cata atOr atAnd atFalse atTrue atBase a2)
-
-    type UnionOfConjunctions = (Component * int * int) list list
-
-    let toUnion (ac : AcceptanceCriterion) : UnionOfConjunctions =
-        cata
-            List.append
-            (fun l1 l2 -> [ List.concat (l1 @ l2) ])
-            (fun () -> failwith "no falses")
-            (fun () -> failwith "no trues")
-            (fun comp low high -> [ [ comp, low, high ] ])
-            ac
+        | Base (comp, low, high) ->
+            match comp with
+            | Component.A ->
+                { Conjunction.All with
+                    A =
+                        {
+                            Low = low
+                            High = high
+                        }
+                }
+            | Component.M ->
+                { Conjunction.All with
+                    M =
+                        {
+                            Low = low
+                            High = high
+                        }
+                }
+            | Component.S ->
+                { Conjunction.All with
+                    S =
+                        {
+                            Low = low
+                            High = high
+                        }
+                }
+            | Component.X ->
+                { Conjunction.All with
+                    X =
+                        {
+                            Low = low
+                            High = high
+                        }
+                }
+            | _ -> failwith "bad"
+            |> List.singleton
+        | And (a, b) ->
+            [
+                Conjunction.conjAnd (List.exactlyOne (toUnion a)) (List.exactlyOne (toUnion b))
+            ]
+        | Or (a, b) -> toUnion a @ toUnion b
+        | True -> failwith "already stripped out"
+        | False -> failwith "already stripped out"
 
     let rec acceptance
         (store : Dictionary<string, AcceptanceCriterion>)
@@ -219,46 +321,37 @@ module Day19 =
 
         let rules, final = workflows.[key]
 
-        let seed =
+        let mutable result =
             match final with
             | Register s -> acceptance store workflows s
             | Accept -> AcceptanceCriterion.True
             | Reject -> AcceptanceCriterion.False
 
-        let result =
-            (seed, Seq.rev rules)
-            ||> Seq.fold (fun crit rule ->
+        for i = rules.Count - 1 downto 0 do
+            let rule = rules.[i]
+
+            let cond =
+                if rule.IsLess then
+                    AcceptanceCriterion.Base (rule.Component, 1, rule.Operand - 1)
+                else
+                    AcceptanceCriterion.Base (rule.Component, rule.Operand + 1, 4000)
+
+            let negCond =
+                if rule.IsLess then
+                    AcceptanceCriterion.Base (rule.Component, rule.Operand, 4000)
+                else
+                    AcceptanceCriterion.Base (rule.Component, 1, rule.Operand)
+
+            result <-
                 match rule.Target with
-                | Register target ->
-                    let cond =
-                        if rule.IsLess then
-                            AcceptanceCriterion.Base (rule.Component, 1, rule.Operand - 1)
-                        else
-                            AcceptanceCriterion.Base (rule.Component, rule.Operand + 1, 4000)
-
-                    acOr (acAnd cond (acceptance store workflows target)) crit
-                | Accept ->
-                    let cond =
-                        if rule.IsLess then
-                            AcceptanceCriterion.Base (rule.Component, 1, rule.Operand - 1)
-                        else
-                            AcceptanceCriterion.Base (rule.Component, rule.Operand + 1, 4000)
-
-                    acOr cond crit
-                | Reject ->
-                    let negCond =
-                        if not rule.IsLess then
-                            AcceptanceCriterion.Base (rule.Component, 1, rule.Operand - 1)
-                        else
-                            AcceptanceCriterion.Base (rule.Component, rule.Operand + 1, 4000)
-
-                    acAnd negCond crit
-            )
+                | Register target -> acOr (acAnd cond (acceptance store workflows target)) (acAnd negCond result)
+                | Accept -> acOr cond (acAnd negCond result)
+                | Reject -> acAnd negCond result
 
         store.[key] <- result
         result
 
-    let part2 (s : string) =
+    let part2 (s : string) : uint64 =
         use mutable rows = StringSplitEnumerator.make '\n' s
         let workflows = readWorkflows &rows
 
@@ -267,8 +360,4 @@ module Day19 =
         let a = acceptance acceptanceRanges workflows "in"
         let union = toUnion a
 
-        printfn "%+A" a
-        printfn "%+A" union
-
-        //uint64 (IntervalSet.count resolved.X) * uint64 (IntervalSet.count resolved.M) * uint64 (IntervalSet.count resolved.A) * uint64 (IntervalSet.count resolved.S)
-        0uL
+        union |> List.sumBy Conjunction.size

AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/List.fs

@@ -0,0 +1,38 @@
+namespace AdventOfCode2023
+
+open System
+
+[<RequireQualifiedAccess>]
+module List =
+    let rec nTuples (n : int) (xs : 'a list) : 'a list list =
+#if DEBUG
+        if n < 0 then
+            raise (ArgumentException "n cannot be negative")
+#endif
+        match n, xs with
+        | 0, _ -> [ [] ]
+        | _, [] -> []
+        | _, x :: xs ->
+            let withX = nTuples (n - 1) xs |> List.map (fun xs -> x :: xs)
+            let withoutX = nTuples n xs
+            withX @ withoutX
+
+    let inline inclusionExclusion (sizeOf : 'a -> 'ret) (sizeOfTuple : 'a list -> 'ret) (xs : 'a list) : 'ret =
+        let mutable result = List.sumBy sizeOf xs
+        let mutable i = 2
+
+        while i <= xs.Length do
+            let nTuples = nTuples i xs
+            let sum = List.sumBy sizeOfTuple nTuples
+
+            if sum = LanguagePrimitives.GenericZero then
+                i <- Int32.MaxValue
+            else
+                if i % 2 = 0 then
+                    result <- result - sum
+                else
+                    result <- result + sum
+
+                i <- i + 1
+
+        result

AdventOfCode2023.FSharp/Test/Test.fsproj

@@ -13,6 +13,7 @@
   <ItemGroup>
     <Compile Include="Util.fs"/>
     <Compile Include="TestIntervalSet.fs" />
+    <Compile Include="TestList.fs" />
     <Compile Include="TestDay1.fs"/>
     <Compile Include="TestDay2.fs"/>
     <Compile Include="TestDay3.fs"/>

AdventOfCode2023.FSharp/Test/TestDay19.fs

@@ -7,7 +7,6 @@ open System.IO
 
 [<TestFixture>]
 module TestDay19 =
-
     [<Test>]
     let sample = Assembly.getEmbeddedResource typeof<Dummy>.Assembly "day19.txt"
 
@@ -43,4 +42,4 @@ module TestDay19 =
                 Assert.Inconclusive ()
                 failwith "unreachable"
 
-        Day19.part2 s |> shouldEqual 8314uL
+        Day19.part2 s |> shouldEqual 127675188176682uL

AdventOfCode2023.FSharp/Test/TestList.fs

@@ -0,0 +1,20 @@
+namespace Test
+
+open NUnit.Framework
+open FsUnitTyped
+open FsCheck
+open AdventOfCode2023
+
+[<TestFixture>]
+module TestList =
+
+    [<Test>]
+    let ``n-tuples have the right length`` () =
+        let property (n : int) (xs : char list) =
+            let n = min (abs n) 6
+            let xs = xs |> List.take (min 10 xs.Length)
+            let tuples = List.nTuples n xs
+            tuples |> List.forall (fun i -> i.Length = n)
+
+        property 1 [ 'v' ] |> shouldEqual true
+        Check.QuickThrowOnFailure property