Day 25

Author: WVerlaek

src/main/kotlin/y24/Day25.kt

@@ -0,0 +1,57 @@
+package y24
+
+import common.puzzle.solvePuzzle
+import common.puzzle.Input
+import common.puzzle.Puzzle
+import common.datastructures.*
+import common.ext.*
+import common.util.*
+import java.util.*
+import kotlin.math.*
+import kotlin.system.exitProcess
+
+
+fun main() = solvePuzzle(year = 2024, day = 25) { Day25(it) }
+
+class Day25(val input: Input) : Puzzle {
+
+    private fun parseInput(lines: List<String>): Pair<List<List<Int>>, List<List<Int>>> {
+        val locks = mutableListOf<List<Int>>()
+        val keys = mutableListOf<List<Int>>()
+
+        var i = 0
+        while (i < lines.size) {
+            if (lines[i].all { it == '#' }) {
+                locks += sequence(lines.subList(i, i + 7))
+            } else {
+                keys += sequence(lines.subList(i, i + 7).reversed())
+            }
+            i += 8
+        }
+
+        return locks to keys
+    }
+
+    private fun sequence(lines: List<String>): List<Int> {
+        return IntArray(lines[0].length) { i ->
+            lines.indexOfFirst { it[i] == '.' } - 1
+        }.toList()
+    }
+
+    private fun fits(lock: List<Int>, key: List<Int>): Boolean {
+        return lock.indices.all { i -> lock[i] + key[i] < 6 }
+    }
+
+    override fun solveLevel1(): Any {
+        val (locks, keys) = parseInput(input.lines)
+        return locks.sumOf { lock ->
+            keys.count { key ->
+                fits(lock, key)
+            }
+        }
+    }
+
+    override fun solveLevel2(): Any {
+        TODO()
+    }
+}

src/test/kotlin/y24/Day25Test.kt

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+package y24
+
+import common.puzzle.Input
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+internal class Day25Test {
+    private val sample = Input("""
+    #####
+    .####
+    .####
+    .####
+    .#.#.
+    .#...
+    .....
+    
+    #####
+    ##.##
+    .#.##
+    ...##
+    ...#.
+    ...#.
+    .....
+    
+    .....
+    #....
+    #....
+    #...#
+    #.#.#
+    #.###
+    #####
+    
+    .....
+    .....
+    #.#..
+    ###..
+    ###.#
+    ###.#
+    #####
+    
+    .....
+    .....
+    .....
+    #....
+    #.#..
+    #.#.#
+    #####
+    """.trimIndent())
+
+    private val day = Day25(sample)
+
+    @Test
+    fun solveLevel1() {
+        assertEquals(3, day.solveLevel1())
+    }
+
+    @Test
+    fun solveLevel2() {
+        // assertEquals(, day.solveLevel2())
+    }
+}