Solve day 3

2024/src/main/kotlin/aoc/year2024/Day3.kt

@@ -0,0 +1,25 @@
+package aoc.year2024
+
+import aoc.library.Puzzle
+
+object Day3 : Puzzle<Long, Long>(day = 3) {
+
+  override fun solvePart1(input: String): Long = runMultiplications(input)
+
+  override fun solvePart2(input: String): Long = runMultiplications(clean(input))
+
+  private fun clean(input: String): String {
+    val firstDont = input.indexOf("don't()")
+    if (firstDont == -1) return input
+    val firstDo = input.indexOf("do()", startIndex = firstDont)
+    if (firstDo == -1) return input
+    return clean(input.take(firstDont) + input.drop(firstDo + 4))
+  }
+
+  private fun runMultiplications(input: String): Long {
+    val regex = """mul\((\d+),(\d+)\)""".toRegex()
+    return regex.findAll(input).map {
+      it.groupValues[1].toLong() * it.groupValues[2].toLong()
+    }.sum()
+  }
+}

2024/src/test/kotlin/aoc/year2024/Day3Test.kt

@@ -0,0 +1,29 @@
+package aoc.year2024
+
+import aoc.library.solvePart1
+import aoc.library.solvePart2
+import io.kotest.matchers.longs.shouldBeExactly
+import org.junit.jupiter.api.Test
+
+class Day3Test {
+
+  @Test
+  fun part1TestInput() {
+    Day3.solvePart1("xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))") shouldBeExactly 161
+  }
+
+  @Test
+  fun part1() {
+    Day3.solvePart1() shouldBeExactly 175015740
+  }
+
+  @Test
+  fun part2TestInput() {
+    Day3.solvePart2("xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))") shouldBeExactly 48
+  }
+
+  @Test
+  fun part2() {
+    Day3.solvePart2() shouldBeExactly 112272912
+  }
+}