2024-11 Rust & Scala 2

Author: jurisk

rust/Cargo.lock

@@ -14,3 +14,4 @@ advent-of-code-common = { path = "../common" }
 chumsky.workspace = true
 itertools.workspace = true
 regex.workspace = true
+memoize.workspace = true

rust/y2024/Cargo.toml

@@ -0,0 +1,67 @@
+use memoize::memoize;
+
+type N = u64;
+
+const DATA: [N; 8] = [6_563_348, 67, 395, 0, 6, 4425, 89567, 739_318];
+
+type R = usize;
+
+#[expect(
+    clippy::cast_possible_truncation,
+    clippy::cast_sign_loss,
+    clippy::cast_precision_loss
+)]
+fn halves(n: N) -> Option<(N, N)> {
+    let digits = (n as f64).log10() as usize + 1;
+    (digits % 2 == 0).then_some({
+        let half_length = digits / 2;
+        let divisor = 10u64.pow(half_length as u32);
+        let left = n / divisor;
+        let right = n % divisor;
+        (left, right)
+    })
+}
+
+#[memoize]
+#[allow(clippy::collapsible_else_if)]
+fn solve_one(n: N, blinks: usize) -> R {
+    if blinks == 0 {
+        1
+    } else {
+        if n == 0 {
+            solve_one(1, blinks - 1)
+        } else {
+            match halves(n) {
+                Some((left, right)) => solve_one(left, blinks - 1) + solve_one(right, blinks - 1),
+                None => solve_one(n * 2024, blinks - 1),
+            }
+        }
+    }
+}
+
+fn solve(data: &[N], blinks: usize) -> R {
+    data.iter().map(|n| solve_one(*n, blinks)).sum()
+}
+
+fn main() {
+    let result_1 = solve(&DATA, 25);
+    println!("Part 1: {result_1}");
+
+    let result_2 = solve(&DATA, 75);
+    println!("Part 2: {result_2}");
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_solve_1_real() {
+        assert_eq!(solve(&DATA, 25), 184_927);
+    }
+
+    #[test]
+    fn test_solve_2_real() {
+        assert_eq!(solve(&DATA, 75), 220_357_186_726_677);
+    }
+}

rust/y2024/src/bin/solution_2024_11.rs

@@ -0,0 +1 @@
+noop

scala2/src/main/resources/2024/11-test-00.txt

@@ -0,0 +1 @@
+noop

scala2/src/main/resources/2024/11.txt

@@ -1,47 +1,70 @@
 package jurisk.adventofcode.y2024
 
-import jurisk.utils.FileInput._
-import jurisk.utils.Parsing.StringOps
+import jurisk.math.pow
+import jurisk.utils.Memoize
+import mouse.all.booleanSyntaxMouse
+
+import scala.math.log10
 
 object Advent11 {
-  type Input = List[Command]
+  type Input = Vector[Long]
   type N     = Long
 
-  sealed trait Command extends Product with Serializable
-  object Command {
-    case object Noop                      extends Command
-    final case class Something(
-      values: List[N]
-    ) extends Command
-    final case class Other(value: String) extends Command
-
-    def parse(s: String): Command =
-      s match {
-        case "noop"            => Noop
-        case s"something $rem" => Something(rem.extractLongList)
-        case s if s.nonEmpty   => Other(s)
-        case _                 => s.failedToParse
-      }
+  private def halves(n: Long): Option[(Long, Long)] = {
+    val digits = log10(n.doubleValue).toInt + 1
+
+    (digits % 2 == 0).option {
+      val halfLength = digits / 2
+      val divisor    = pow(10, halfLength)
+      val left       = n / divisor
+      val right      = n % divisor
+      (left, right)
+    }
   }
 
-  def parse(input: String): Input =
-    input.parseLines(Command.parse)
+  def blink(data: Input): Input =
+    data.flatMap { n =>
+      if (n == 0) {
+        Vector(1)
+      } else {
+        halves(n) match {
+          case Some((left, right)) =>
+            Vector(left, right)
+          case None                =>
+            Vector(n * 2024)
+        }
+      }
+    }
 
-  def part1(data: Input): N =
-    0
+  private val memoizedSolve: (Long, Int) => N   = Memoize.memoize2(solve)
+  private def solve(n: Long, blinks: Int): Long =
+    if (blinks <= 0) {
+      1
+    } else {
+      if (n == 0) {
+        memoizedSolve(1, blinks - 1)
+      } else {
+        halves(n) match {
+          case Some((left, right)) =>
+            memoizedSolve(left, blinks - 1) + memoizedSolve(right, blinks - 1)
+          case None                =>
+            memoizedSolve(n * 2024, blinks - 1)
+        }
+      }
+    }
 
-  def part2(data: Input): N =
-    0
+  def blinkNTimes(data: Input, blinks: Int): Input =
+    (0 until blinks).foldLeft(data)((acc, _) => blink(acc))
 
-  def parseFile(fileName: String): Input =
-    parse(readFileText(fileName))
+  def part1(data: Input, blinks: Int = 25): N =
+    blinkNTimes(data, blinks).size
 
-  def fileName(suffix: String): String =
-    s"2024/11$suffix.txt"
+  def part2(data: Input, blinks: Int = 75): N =
+    data.map(n => memoizedSolve(n, blinks)).sum
 
-  def main(args: Array[String]): Unit = {
-    val realData: Input = parseFile(fileName(""))
+  val realData: Input = Vector(6563348, 67, 395, 0, 6, 4425, 89567, 739318)
 
+  def main(args: Array[String]): Unit = {
     println(s"Part 1: ${part1(realData)}")
     println(s"Part 2: ${part2(realData)}")
   }

scala2/src/main/resources/2024/12-test-00.txt

@@ -0,0 +1,48 @@
+package jurisk.adventofcode.y2024
+
+import jurisk.utils.FileInput._
+import jurisk.utils.Parsing.StringOps
+
+object Advent12 {
+  type Input = List[Command]
+  type N     = Long
+
+  sealed trait Command extends Product with Serializable
+  object Command {
+    case object Noop                      extends Command
+    final case class Something(
+      values: List[N]
+    ) extends Command
+    final case class Other(value: String) extends Command
+
+    def parse(s: String): Command =
+      s match {
+        case "noop"            => Noop
+        case s"something $rem" => Something(rem.extractLongList)
+        case s if s.nonEmpty   => Other(s)
+        case _                 => s.failedToParse
+      }
+  }
+
+  def parse(input: String): Input =
+    input.parseLines(Command.parse)
+
+  def part1(data: Input): N =
+    0
+
+  def part2(data: Input): N =
+    0
+
+  def parseFile(fileName: String): Input =
+    parse(readFileText(fileName))
+
+  def fileName(suffix: String): String =
+    s"2024/12$suffix.txt"
+
+  def main(args: Array[String]): Unit = {
+    val realData: Input = parseFile(fileName(""))
+
+    println(s"Part 1: ${part1(realData)}")
+    println(s"Part 2: ${part2(realData)}")
+  }
+}

scala2/src/main/resources/2024/12.txt

@@ -5,26 +5,27 @@ import org.scalatest.freespec.AnyFreeSpec
 import org.scalatest.matchers.should.Matchers._
 
 class Advent11Spec extends AnyFreeSpec {
-  private def testData = parseFile(fileName("-test-00"))
-  private def realData = parseFile(fileName(""))
-
   "part 1" - {
     "test" in {
-      part1(testData) shouldEqual 0
+      blink(Vector(0, 1, 10, 99, 999)) shouldEqual Vector(1, 2024, 1, 0, 9, 9,
+        2021976)
+      blink(Vector(125, 17)) shouldEqual Vector(253000, 1, 7)
+      blinkNTimes(Vector(125, 17), 2) shouldEqual Vector(253, 0, 2024, 14168)
+      part1(Vector(125, 17), 6) shouldEqual 22
+      part1(Vector(125, 17)) shouldEqual 55312
     }
 
     "real" in {
-      part1(realData) shouldEqual 0
+      part1(realData) shouldEqual 184927
     }
   }
 
   "part 2" - {
-    "test" in {
-      part2(testData) shouldEqual 0
+    "real 25" in {
+      part2(realData, 25) shouldEqual 184927
     }
-
-    "real" in {
-      part2(realData) shouldEqual 0
+    "real 75" in {
+      part2(realData) shouldEqual 220357186726677L
     }
   }
 }

scala2/src/main/scala/jurisk/adventofcode/y2024/Advent11.scala

@@ -0,0 +1,30 @@
+package jurisk.adventofcode.y2024
+
+import Advent12._
+import org.scalatest.freespec.AnyFreeSpec
+import org.scalatest.matchers.should.Matchers._
+
+class Advent12Spec extends AnyFreeSpec {
+  private def testData = parseFile(fileName("-test-00"))
+  private def realData = parseFile(fileName(""))
+
+  "part 1" - {
+    "test" in {
+      part1(testData) shouldEqual 0
+    }
+
+    "real" in {
+      part1(realData) shouldEqual 0
+    }
+  }
+
+  "part 2" - {
+    "test" in {
+      part2(testData) shouldEqual 0
+    }
+
+    "real" in {
+      part2(realData) shouldEqual 0
+    }
+  }
+}

scala2/src/main/scala/jurisk/adventofcode/y2024/Advent12.scala

@@ -1,32 +1,36 @@
 package jurisk.adventofcode.y2020
 
-import scala.io.Source
-
-object Advent02 extends App:
-  final case class Item(
-    a: Int,
-    b: Int,
-    letter: Char,
-    password: String,
-  ):
-    def isValid1: Boolean =
-      val count = password.count(_ == letter)
-      (count >= a) && (count <= b)
-
-    def isValid2: Boolean =
-      List(password(a - 1), password(b - 1)).count(_ == letter) == 1
-
-  def parse(x: String): Item =
+import jurisk.adventofcode.AdventApp.ErrorMessage
+import jurisk.adventofcode.SingleLineAdventApp
+import cats.implicits._
+
+final case class Item(
+  a: Int,
+  b: Int,
+  letter: Char,
+  password: String,
+):
+  def isValid1: Boolean =
+    val count = password.count(_ == letter)
+    (count >= a) && (count <= b)
+
+  def isValid2: Boolean =
+    List(password(a - 1), password(b - 1)).count(_ == letter) == 1
+
+object Advent02 extends SingleLineAdventApp[Item, Int]:
+  val year: Int = 2020
+  val exercise: Int = 2
+
+  override def parseLine(line: String): Either[ErrorMessage, Item] = {
     val Pattern = """(\d+)-(\d+) (\w): (\w+)""".r
-    x match
+
+    line match
       case Pattern(a, b, letter, password) if letter.length == 1 =>
-        Item(a.toInt, b.toInt, letter.head, password)
+        Item(a.toInt, b.toInt, letter.head, password).asRight
       case _ =>
-        sys.error(s"Couldn't parse $x")
-
-  val list = Source.fromResource("2020/02.txt").getLines().map(parse).toList
-  
-  def solve(f: Item => Boolean): Unit =
-    println(list.count(f))
-  
-  List[Item => Boolean](_.isValid1, _.isValid2) foreach solve
+        ErrorMessage(s"Couldn't parse $line").asLeft
+  }
+
+  override def solution1(input: List[Item]): Int = input.count(_.isValid1)
+
+  override def solution2(input: List[Item]): Int = input.count(_.isValid2)