Christmas

src/main/kotlin/y2024/day25/Day25.kt

@@ -0,0 +1,33 @@
+package y2024.day25
+
+import utils.getInputFile
+import utils.toPointGrid
+
+fun main() {
+    println("Part one: " + Day25().solvePartOne())
+}
+
+class Day25 {
+
+    private val locks: List<Map<Int, Int>>
+    private val keys: List<Map<Int, Int>>
+
+    init {
+        val (lockIn, keyIn) = getInputFile(example = false)
+            .readText()
+            .split("\n\n")
+            .partition { it.first() == '#' }
+        locks = lockIn.map { it.lines().toPointGrid().filterValues { it == '#' }.keys.groupingBy { it.x }.eachCount() }
+        keys = keyIn.map { it.lines().toPointGrid().filterValues { it == '#' }.keys.groupingBy { it.x }.eachCount() }
+    }
+
+    fun solvePartOne(): Int {
+        return locks.sumOf { lock ->
+            keys.count { key ->
+                lock.entries.all { (x, c) ->
+                    key.getValue(x) + c <= 7
+                }
+            }
+        }
+    }
+}

src/test/kotlin/y2024/day25/Day25Test.kt

@@ -0,0 +1,13 @@
+package y2024.day25
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+internal class Day25Test {
+
+
+    @Test
+    fun solvePartOne() {
+        assertEquals(3114, Day25().solvePartOne())
+    }
+}