From cb8122da59bc3468e534fa3087d73c1f577655cd Mon Sep 17 00:00:00 2001
From: Simmo Saan <simmo.saan@gmail.com>
Date: Wed, 6 Dec 2023 08:15:28 +0200
Subject: [PATCH] Solve 2023 day 6 part 1

---
 .../eu/sim642/adventofcode2023/day6.txt       |  2 ++
 .../eu/sim642/adventofcode2023/Day6.scala     | 26 +++++++++++++++++++
 .../eu/sim642/adventofcode2023/Day6Test.scala | 19 ++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 src/main/resources/eu/sim642/adventofcode2023/day6.txt
 create mode 100644 src/main/scala/eu/sim642/adventofcode2023/Day6.scala
 create mode 100644 src/test/scala/eu/sim642/adventofcode2023/Day6Test.scala

diff --git a/src/main/resources/eu/sim642/adventofcode2023/day6.txt b/src/main/resources/eu/sim642/adventofcode2023/day6.txt
new file mode 100644
index 00000000..f3805ad9
--- /dev/null
+++ b/src/main/resources/eu/sim642/adventofcode2023/day6.txt
@@ -0,0 +1,2 @@
+Time:        48     93     85     95
+Distance:   296   1928   1236   1391
diff --git a/src/main/scala/eu/sim642/adventofcode2023/Day6.scala b/src/main/scala/eu/sim642/adventofcode2023/Day6.scala
new file mode 100644
index 00000000..ec51cf7d
--- /dev/null
+++ b/src/main/scala/eu/sim642/adventofcode2023/Day6.scala
@@ -0,0 +1,26 @@
+package eu.sim642.adventofcode2023
+
+object Day6 {
+
+  case class Race(time: Int, recordDistance: Int) {
+    def wins: Int = {
+      (0 to time).count(t => t * (time - t) > recordDistance)
+    }
+  }
+
+  def multiplyRaceWins(races: Seq[Race]): Int = races.map(_.wins).product
+
+
+  def parseRaces(input: String): Seq[Race] = input.linesIterator.toSeq match {
+    case Seq(s"Time:$timesStr", s"Distance:$distancesStr") =>
+      val times = timesStr.trim.split(" +").map(_.toInt).toSeq
+      val distances = distancesStr.trim.split(" +").map(_.toInt).toSeq
+      (times lazyZip distances).map(Race.apply)
+  }
+
+  lazy val input: String = io.Source.fromInputStream(getClass.getResourceAsStream("day6.txt")).mkString.trim
+
+  def main(args: Array[String]): Unit = {
+    println(multiplyRaceWins(parseRaces(input)))
+  }
+}
diff --git a/src/test/scala/eu/sim642/adventofcode2023/Day6Test.scala b/src/test/scala/eu/sim642/adventofcode2023/Day6Test.scala
new file mode 100644
index 00000000..e349d85c
--- /dev/null
+++ b/src/test/scala/eu/sim642/adventofcode2023/Day6Test.scala
@@ -0,0 +1,19 @@
+package eu.sim642.adventofcode2023
+
+import Day6._
+import org.scalatest.funsuite.AnyFunSuite
+
+class Day6Test extends AnyFunSuite {
+
+  private val exampleInput =
+    """Time:      7  15   30
+      |Distance:  9  40  200""".stripMargin
+
+  test("Part 1 examples") {
+    assert(multiplyRaceWins(parseRaces(exampleInput)) == 288)
+  }
+
+  test("Part 1 input answer") {
+    assert(multiplyRaceWins(parseRaces(input)) == 2756160)
+  }
+}