Fit in uint32

AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day7.fs

@@ -24,13 +24,16 @@ type HandContents =
 [<RequireQualifiedAccess>]
 module Day7 =
 
+    [<Literal>]
+    let joker = 0uy
+
     let inline toByte (adjustJoker : bool) (c : char) : byte =
-        if c <= '9' then byte c - byte '0'
-        elif c = 'T' then 10uy
-        elif c = 'J' then (if adjustJoker then 1uy else 11uy)
-        elif c = 'Q' then 12uy
-        elif c = 'K' then 13uy
-        elif c = 'A' then 14uy
+        if c <= '9' then byte c - byte '1'
+        elif c = 'T' then 9uy
+        elif c = 'J' then (if adjustJoker then joker else 10uy)
+        elif c = 'Q' then 11uy
+        elif c = 'K' then 12uy
+        elif c = 'A' then 13uy
         else failwithf "could not parse: %c" c
 
     let inline private updateState (tallies : ResizeArray<_>) newNum =
@@ -44,10 +47,10 @@ module Day7 =
         if not isAdded then
             tallies.Add (newNum, 1)
 
-    type RankedHand = uint64
+    type RankedHand = uint32
 
     [<Literal>]
-    let fifteen = 15uL
+    let fifteen = 14ul
 
     [<Literal>]
     let fifteenFive = fifteen * fifteen * fifteen * fifteen * fifteen
@@ -61,16 +64,13 @@ module Day7 =
     [<Literal>]
     let fifteenTwo = fifteen * fifteen
 
-    let inline toInt (hand : Hand) (contents : HandContents) : RankedHand =
-        // match hand with
-        // | Hand.Five -> UInt32.MaxValue - 15ul + uint32 contents.First
-        // | _ ->
-        uint64 hand * fifteenFive
-        + uint64 contents.First * fifteenFour
-        + uint64 contents.Second * fifteenThree
-        + uint64 contents.Third * fifteenTwo
-        + uint64 contents.Fourth * fifteen
-        + uint64 contents.Fifth
+    let toInt (hand : Hand) (contents : HandContents) : RankedHand =
+        uint32 hand * fifteenFive
+        + uint32 contents.First * fifteenFour
+        + uint32 contents.Second * fifteenThree
+        + uint32 contents.Third * fifteenTwo
+        + uint32 contents.Fourth * fifteen
+        + uint32 contents.Fifth
 
     let inline parseHand (tallyBuffer : ResizeArray<_>) (adjustJoker : bool) (s : ReadOnlySpan<char>) : RankedHand =
         let contents =
@@ -93,17 +93,17 @@ module Day7 =
             if not adjustJoker then
                 0, -1
             else
-                let mutable count = 0
+                let mutable jokerCount = 0
                 let mutable jokerPos = -1
 
                 for i = 0 to tallyBuffer.Count - 1 do
                     let card, tally = tallyBuffer.[i]
 
-                    if card = 1uy then
-                        count <- tally
+                    if card = joker then
+                        jokerCount <- tally
                         jokerPos <- i
 
-                count, jokerPos
+                jokerCount, jokerPos
 
         let hand =
             if jokerCount > 0 then
@@ -160,11 +160,14 @@ module Day7 =
 
         toInt hand contents
 
-    type RankedHandAndBid = uint64
+    type RankedHandAndBid = uint32
 
-    let inline toRankedHandAndBid (r : RankedHand) (bid : uint64) : RankedHandAndBid = 1001uL * r + bid
+    [<Literal>]
+    let bidSeparator = 1001ul
 
-    let inline getBid (r : RankedHandAndBid) : uint64 = uint64 (r % 1001uL)
+    let inline toRankedHandAndBid (r : RankedHand) (bid : uint32) : RankedHandAndBid = bidSeparator * r + bid
+
+    let inline getBid (r : RankedHandAndBid) : uint32 = uint32 (r % bidSeparator)
 
     let parse (adjustJoker : bool) (s : string) : ResizeArray<RankedHandAndBid> =
         use mutable lines = StringSplitEnumerator.make '\n' s
@@ -179,7 +182,7 @@ module Day7 =
                 line.MoveNext () |> ignore
 
                 let bid =
-                    UInt64.Parse (line.Current, NumberStyles.Integer, CultureInfo.InvariantCulture)
+                    UInt32.Parse (line.Current, NumberStyles.Integer, CultureInfo.InvariantCulture)
 
                 result.Add (toRankedHandAndBid rankedHand bid)
 
@@ -190,10 +193,10 @@ module Day7 =
 
         arr.Sort ()
 
-        let mutable answer = 0uL
+        let mutable answer = 0ul
 
         for i = 0 to arr.Count - 1 do
-            answer <- answer + getBid arr.[i] * (uint64 i + 1uL)
+            answer <- answer + getBid arr.[i] * (uint32 i + 1ul)
 
         answer
 
@@ -202,9 +205,9 @@ module Day7 =
 
         arr.Sort ()
 
-        let mutable answer = 0uL
+        let mutable answer = 0ul
 
         for i = 0 to arr.Count - 1 do
-            answer <- answer + getBid arr.[i] * (uint64 i + 1uL)
+            answer <- answer + getBid arr.[i] * (uint32 i + 1ul)
 
         answer

AdventOfCode2023.FSharp/Test/TestDay7.fs

@@ -13,11 +13,11 @@ module TestDay7 =
 
     [<Test>]
     let part1Sample () =
-        sample |> Day7.part1 |> shouldEqual 6440uL
+        sample |> Day7.part1 |> shouldEqual 6440ul
 
     [<Test>]
     let part2Sample () =
-        sample |> Day7.part2 |> shouldEqual 5905uL
+        sample |> Day7.part2 |> shouldEqual 5905ul
 
     [<Test>]
     let part1Actual () =
@@ -30,7 +30,7 @@ module TestDay7 =
                 Assert.Inconclusive ()
                 failwith "unreachable"
 
-        Day7.part1 s |> shouldEqual 250058342uL
+        Day7.part1 s |> shouldEqual 250058342ul
 
     [<Test>]
     let part2Actual () =
@@ -43,4 +43,4 @@ module TestDay7 =
                 Assert.Inconclusive ()
                 failwith "unreachable"
 
-        Day7.part2 s |> shouldEqual 250506580uL
+        Day7.part2 s |> shouldEqual 250506580ul