Day 25.

src/aoc2024/Day25.kt

@@ -0,0 +1,91 @@
+package aoc2024
+
+import CharGrid
+import println
+import readInput
+
+/*
+--- Day 25: Code Chronicle ---
+https://adventofcode.com/2024/day/25
+*/
+fun main() {
+
+    val inlineTestInput = """
+#####
+.####
+.####
+.####
+.#.#.
+.#...
+.....
+
+#####
+##.##
+.#.##
+...##
+...#.
+...#.
+.....
+
+.....
+#....
+#....
+#...#
+#.#.#
+#.###
+#####
+
+.....
+.....
+#.#..
+###..
+###.#
+###.#
+#####
+
+.....
+.....
+.....
+#....
+#.#..
+#.#.#
+#####
+"""
+
+    fun part1(input: List<String>): Int {
+        var p = 0
+        val topRow = IntRange(0, 4)
+        val locks = ArrayList<IntArray>()
+        val keys = ArrayList<IntArray>()
+        while (p < input.size) {
+            val grid = CharGrid(input.subList(p, p + 7))
+            if (topRow.all { grid[it, 0] == '#' }) {
+                val lock = topRow.map { rc -> (topRow.find { grid[rc, it + 1] != '#' } ?: 5) }.toIntArray()
+                locks.add(lock)
+            } else {
+                val key = topRow.map { rc -> 5 - (topRow.find { grid[rc, 5 - it] != '#' } ?: 5) }.toIntArray()
+                keys.add(key)
+            }
+            p += 8
+        }
+        return locks.sumOf { lock -> keys.count { key -> key.zip(lock).all { it.first >= it.second } } }
+    }
+
+    fun part2(input: List<String>): Int {
+        return 0
+    }
+
+    // test if implementation meets criteria from the description, like:
+    val testInput = inlineTestInput.trim().reader().readLines()
+    //val testInput = readInput("aoc2024/Day25_test")
+    val testInputPart1Result = part1(testInput)
+    println("Part 1 Test: $testInputPart1Result")
+    val testInputPart2Result = part2(testInput)
+    println("Part 2 Test: $testInputPart2Result")
+    check(testInputPart1Result == 3)
+    check(testInputPart2Result == 0)
+
+    val input = readInput("aoc2024/Day25")
+    part1(input).println()
+    part2(input).println()
+}