Solved day19 part 1

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2023'
-version '0.18.4'
+version '0.18.5'
 
 // Switch to gradle "all" distribution.
 wrapper {

day19/src/main/kotlin/de/havox_design/aoc2023/day19/Assignment.kt

@@ -0,0 +1,11 @@
+package de.havox_design.aoc2023.day19
+
+data class Assignment(
+    val x: Long,
+    val m: Long,
+    val a: Long,
+    val s: Long
+) {
+    fun total() =
+        x + m + a + s
+}

day19/src/main/kotlin/de/havox_design/aoc2023/day19/Condition.kt

@@ -0,0 +1,27 @@
+package de.havox_design.aoc2023.day19
+
+data class Condition(
+    val field: Char,
+    val lessThen: Boolean,
+    val value: Long,
+    val successLabel: String
+) {
+    private val ICON_EXTREMELY_COOL_LOOKING = 'x'
+    private val ICON_MUSICAL = 'm'
+    private val ICON_AERODYNAMIC = 'a'
+    private val ICON_SHINY = 's'
+
+    fun test(assignment: Assignment): Boolean {
+        val target = when (field) {
+            ICON_EXTREMELY_COOL_LOOKING -> assignment.x
+            ICON_MUSICAL -> assignment.m
+            ICON_AERODYNAMIC -> assignment.a
+            ICON_SHINY -> assignment.s
+            else -> error(this)
+        }
+        return when (lessThen) {
+            true -> target < value
+            else -> target > value
+        }
+    }
+}

day19/src/main/kotlin/de/havox_design/aoc2023/day19/Day19.kt

@@ -1,12 +1,76 @@
 package de.havox_design.aoc2023.day19
 
 class Day19(private var filename: String) {
-    fun solvePart1(): Long =
-        19114L
+    private val ICON_ACCEPT = "A"
+    private val ICON_REJECT = "R"
+    private val ICON_START = "in"
+    private val ICON_LESS_THAN = '<'
+    private val ELEMENT_DELIMITER = ','
+    private val RULE_START_DELIMITER = '{'
+    private val SOLUTION_DELIMITER = ':'
+
+    @SuppressWarnings("kotlin:S6611")
+    fun solvePart1(): Long {
+        val (rules, assignments) = readInput()
+
+        return assignments
+            .filter { assignment ->
+                var current = ICON_START
+
+                while (current != ICON_ACCEPT && current != ICON_REJECT) {
+                    val rule = rules[current]!!
+
+                    current = (rule.decisions.firstOrNull { it.test(assignment) }?.successLabel) ?: rule.elseRule
+                }
+
+                current == ICON_ACCEPT
+            }
+            .sumOf { it.total() }
+    }
 
     fun solvePart2(): Long =
         0L
 
+    private fun readInput(): Pair<Map<String, SortRule>, List<Assignment>> {
+        val input = getResourceAsText(filename)
+
+        val rules = input
+            .takeWhile { it.isNotBlank() }
+            .associate { row ->
+                val (name, rules) = row.split(RULE_START_DELIMITER, limit = 2)
+                val splitRules = rules.split(ELEMENT_DELIMITER)
+                val elseCondition = splitRules.last().dropLast(1)
+                val conditions = splitRules.dropLast(1).map {
+                    val (test, label) = it.split(SOLUTION_DELIMITER, limit = 2)
+                    val conditionName = test.first()
+                    val lessThen = test[1] == ICON_LESS_THAN
+                    val value = test.drop(2).toLong()
+
+                    Condition(conditionName, lessThen, value, label)
+                }
+                name to SortRule(name, conditions, elseCondition)
+            }
+
+        val regex = Regex("\\{x=(\\d+),m=(\\d+),a=(\\d+),s=(\\d+)}")
+        val assignments = input
+            .dropWhile { it.isNotBlank() }
+            .drop(1)
+            .map { row ->
+                regex
+                    .matchEntire(row)!!
+                    .destructured
+                    .let { (x, m, a, s) ->
+                        Assignment(
+                            x.toLong(),
+                            m.toLong(),
+                            a.toLong(),
+                            s.toLong()
+                        )
+                    }
+            }
+        return rules to assignments
+    }
+
     private fun getResourceAsText(path: String): List<String> =
         this.javaClass.classLoader.getResourceAsStream(path)!!.bufferedReader().readLines()
 }

day19/src/main/kotlin/de/havox_design/aoc2023/day19/SortRule.kt

@@ -0,0 +1,7 @@
+package de.havox_design.aoc2023.day19
+
+data class SortRule(
+    val name: String,
+    val decisions: List<Condition>,
+    val elseRule: String
+)