Solution 2015-02 (I Was Told There Would Be No Math)

Author: rhaendel

src/main/kotlin/de/ronny_h/aoc/year15/day02/IWasToldThereWouldBeNoMath.kt

@@ -0,0 +1,25 @@
+package de.ronny_h.aoc.year15.day02
+
+import de.ronny_h.aoc.AdventOfCode
+
+fun main() = IWasToldThereWouldBeNoMath().run(1586300, 3737498)
+
+class IWasToldThereWouldBeNoMath : AdventOfCode<Int>(2015, 2) {
+    data class Present(val length: Int, val width: Int, val height: Int) {
+        fun surfaces() = listOf(2 * length * width, 2 * width * height, 2 * height * length)
+        fun smallestPerimeter() = 2 * (width + length + height - listOf(width, height, length).max())
+        fun volume() = length * width * height
+    }
+
+    override fun part1(input: List<String>): Int =
+        input.toPresents()
+            .map(Present::surfaces)
+            .sumOf { it.sum() + it.min() / 2 }
+
+    override fun part2(input: List<String>): Int =
+        input.toPresents()
+            .sumOf { it.smallestPerimeter() + it.volume() }
+
+    private fun List<String>.toPresents() = map { it.split("x") }
+        .map { (l, w, h) -> Present(l.toInt(), w.toInt(), h.toInt()) }
+}

src/test/kotlin/de/ronny_h/aoc/year15/day02/IWasToldThereWouldBeNoMathTest.kt

@@ -0,0 +1,25 @@
+package de.ronny_h.aoc.year15.day02
+
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldBe
+
+class IWasToldThereWouldBeNoMathTest : StringSpec({
+
+    "part 1: A present with dimensions 2x3x4 requires 58 square feet of wrapping paper" {
+        val input = listOf("2x3x4")
+        IWasToldThereWouldBeNoMath().part1(input) shouldBe 58
+    }
+    "part 1: A present with dimensions 1x1x10 requires 43 square feet of wrapping paper" {
+        val input = listOf("1x1x10")
+        IWasToldThereWouldBeNoMath().part1(input) shouldBe 43
+    }
+
+    "part 2: A present with dimensions 2x3x4 requires 34 feet of ribbon" {
+        val intput = listOf("2x3x4")
+        IWasToldThereWouldBeNoMath().part2(intput) shouldBe 34
+    }
+    "part 2: A present with dimensions 1x1x10 requires 14 feet of ribbon" {
+        val intput = listOf("1x1x10")
+        IWasToldThereWouldBeNoMath().part2(intput) shouldBe 14
+    }
+})