Solution 2015-12 (JSAbacusFramework.io)

Author: rhaendel

src/main/kotlin/de/ronny_h/aoc/year2015/day12/JSAbacusFramework.kt

@@ -0,0 +1,57 @@
+package de.ronny_h.aoc.year2015.day12
+
+import de.ronny_h.aoc.AdventOfCode
+
+fun main() = JSAbacusFramework().run(111754, 65402)
+
+class JSAbacusFramework : AdventOfCode<Int>(2015, 12) {
+
+    private val numberRegex = "[-]{0,1}[0-9]+".toRegex()
+
+    override fun part1(input: List<String>) = input.first().sumAllNumbers()
+
+    override fun part2(input: List<String>) = input.first().filterOutRedObjects().first.sumAllNumbers()
+
+    private fun String.sumAllNumbers(): Int = numberRegex.findAll(this).sumOf { match -> match.value.toInt() }
+}
+
+private const val redValue = ":\"red\""
+
+/**
+ * From a JSON String, filters out sub-objects that have a value equal to "red".
+ *
+ * @return A pair of the filtered JSON String and the length of the JSON object that was processed.
+ */
+fun String.filterOutRedObjects(): Pair<String, Int> {
+    var isRed = false
+    var inRedValue = 0
+    var prefix = ""
+    var i = 0
+    var lastSubObjectAt = 0
+    while (i < length) {
+        when (this[i]) {
+            '{' -> {
+                val (infix, len) = substring(i + 1).filterOutRedObjects()
+                prefix = prefix + substring(lastSubObjectAt..i) + infix
+                i += len
+                lastSubObjectAt = i
+            }
+
+            '}' -> if (isRed) {
+                return "" to i + 1
+            } else {
+                return prefix + substring(lastSubObjectAt, i) to i + 1
+            }
+
+            redValue[inRedValue] -> inRedValue++
+
+            else -> inRedValue = 0
+        }
+        if (inRedValue == redValue.length) {
+            isRed = true
+            inRedValue = 0
+        }
+        i++
+    }
+    return prefix + this.substring(lastSubObjectAt) to length
+}

src/test/kotlin/de/ronny_h/aoc/year2015/day12/JSAbacusFrameworkTest.kt

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+package de.ronny_h.aoc.year2015.day12
+
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldBe
+
+class JSAbacusFrameworkTest : StringSpec({
+
+    val day12 = JSAbacusFramework()
+
+    "part 1: a sum of 6" {
+        day12.part1(listOf("[1,2,3]")) shouldBe 6
+        day12.part1(listOf("{\"a\":2,\"b\":4}")) shouldBe 6
+    }
+
+    "part 1: a sum of 3" {
+        day12.part1(listOf("[[[3]]]")) shouldBe 3
+        day12.part1(listOf("{\"a\":{\"b\":4},\"c\":-1}")) shouldBe 3
+    }
+
+    "part 1: a sum of 0" {
+        day12.part1(listOf("{\"a\":[-1,1]}")) shouldBe 0
+        day12.part1(listOf("[-1,{\"a\":1}]")) shouldBe 0
+        day12.part1(listOf("[]")) shouldBe 0
+        day12.part1(listOf("{}")) shouldBe 0
+    }
+
+    "readNonRedObject of simple array" {
+        "[1,2,3]".filterOutRedObjects() shouldBe Pair("[1,2,3]", 7)
+    }
+
+    "readNonRedObject of simple object" {
+        """{"a":1}""".filterOutRedObjects() shouldBe Pair("""{"a":1}""", 7)
+    }
+
+    "readNonRedObject of simple object containing value red" {
+        """{"a":"red"}""".filterOutRedObjects() shouldBe Pair("{}", 11)
+    }
+
+    "readNonRedObject of nested object" {
+        """{"a":{"b":"c"}}""".filterOutRedObjects() shouldBe Pair("""{"a":{"b":"c"}}""", 15)
+    }
+
+    "readNonRedObject of nested object containing value red" {
+        """{"a":{"b":"red"}}""".filterOutRedObjects() shouldBe Pair("""{"a":{}}""", 17)
+    }
+
+    "readNonRedObject with two red objects on nested level" {
+        """{"a":{"b":"red"},"c":{"d":"red"}}""".filterOutRedObjects() shouldBe Pair("""{"a":{},"c":{}}""", 33)
+    }
+
+    "readNonRedObject of double-nested object" {
+        """{"a":{"b":{"c":"d"}},"e":1}""".filterOutRedObjects() shouldBe Pair(
+            """{"a":{"b":{"c":"d"}},"e":1}""",
+            27
+        )
+    }
+
+    "readNonRedObject of double-nested object containing red" {
+        """{"a":{"b":{"c":"red"},"d":1}}""".filterOutRedObjects() shouldBe Pair("""{"a":{"b":{},"d":1}}""", 29)
+    }
+
+    "readNonRedObject of double-nested object containing red on mid-level" {
+        """{"a":{"b":"red","c":{"d":0},"d":1}}""".filterOutRedObjects() shouldBe Pair("""{"a":{}}""", 35)
+    }
+
+    "part 2: a sum of 6" {
+        day12.part2(listOf("[1,2,3]")) shouldBe 6
+    }
+
+    "part 2: a sum of 4 when ignoring object with a value of red" {
+        day12.part2(listOf("""[1,{"c":"red","b":2},3]""")) shouldBe 4
+    }
+
+    "part 2: a sum of 0 when ignoring object with a value of red" {
+        day12.part2(listOf("""{"d":"red","e":[1,2,3,4],"f":5}""")) shouldBe 0
+    }
+
+    "part 2: a sum of 6 with red in an array" {
+        day12.part2(listOf("""[1,"red",5]""")) shouldBe 6
+    }
+})