Solution 2017-02 (Corruption Checksum)

Author: rhaendel

src/main/kotlin/de/ronny_h/aoc/year2017/day02/CorruptionChecksum.kt

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+package de.ronny_h.aoc.year2017.day02
+
+import de.ronny_h.aoc.AdventOfCode
+import de.ronny_h.aoc.extensions.combinations
+
+fun main() = CorruptionChecksum().run(44216, 320)
+
+class CorruptionChecksum : AdventOfCode<Int>(2017, 2) {
+    override fun part1(input: List<String>): Int = input.sumOf {
+        val ints = it.parseInts()
+        ints.max() - ints.min()
+    }
+
+    override fun part2(input: List<String>): Int = input.sumOf {
+        it.parseInts()
+            .combinations()
+            .forEach { (a, b) ->
+                if (a % b == 0) {
+                    return@sumOf a / b
+                }
+            }
+            .let { return 0 }
+    }
+
+    private fun String.parseInts(): List<Int> = split(" ", "\t").map { it.toInt() }
+}

src/test/kotlin/de/ronny_h/aoc/year2017/day02/CorruptionChecksumTest.kt

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+package de.ronny_h.aoc.year2017.day02
+
+import de.ronny_h.aoc.extensions.asList
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldBe
+
+class CorruptionChecksumTest : StringSpec({
+
+    "part 1: the checksum of the example spreadsheet" {
+        val input = """
+            5 1 9 5
+            7 5 3
+            2 4 6 8
+        """.asList()
+        CorruptionChecksum().part1(input) shouldBe 18
+    }
+
+    "part 2: the sum of evenly divisible values' divide results" {
+        val input = """
+            5 9 2 8
+            9 4 7 3
+            3 8 6 5
+        """.asList()
+        CorruptionChecksum().part2(input) shouldBe 9
+    }
+})