Extract Point class (#17)

src/main/kotlin/days/Day12.kt

@@ -46,23 +46,4 @@ class Day12(val input: List<String>) : Puzzle {
         val sides = corners
     }
 
-    data class Point(val x: Int, val y: Int) {
-        operator fun plus(other: Point) = Point(x + other.x, y + other.y)
-        operator fun minus(other: Point) = Point(x - other.x, y - other.y)
-        operator fun times(o: Int) = Point(x * o, y * o)
-        operator fun Int.times(p: Point) = Point(p.x * this, p.y * this)
-        operator fun List<Point>.contains(p: Point) = any { it == p }
-        fun neighbors(): List<Point> = NEIGHBORS.map { this + it }
-        fun corners() = CORNERS.map { (a, b) -> listOf(this + a, this + a + b, this + b) }
-
-        companion object {
-            private val NORTH = Point(-1, 0)
-            private val WEST = Point(0, -1)
-            private val SOUTH = Point(1, 0)
-            private val EAST = Point(0, 1)
-            val NEIGHBORS = listOf(EAST, SOUTH, WEST, NORTH)
-            val CORNERS = listOf(EAST, SOUTH, WEST, NORTH, EAST).zipWithNext()
-        }
-    }
-
 }

src/main/kotlin/days/Day18.kt

@@ -17,12 +17,12 @@ class Day18(val input: List<String>) : Puzzle {
     private val start = Point(range.start, range.start)
     private val exit = Point(range.last, range.last)
 
-    override fun partOne() = path(bytes)
+    override fun partOne() = distance(bytes)
 
     override fun partTwo(): String = (elements..input.lastIndex).firstNotNullOf {
         val b = input.take(it).map { line -> Point.from(line) }
         try {
-            path(b)
+            distance(b)
             null
         } catch (e: Exception) {
             b.last().let { (x, y) -> "${x},${y}" }
@@ -37,24 +37,7 @@ class Day18(val input: List<String>) : Puzzle {
         }
     }
 
-    data class Point(val x: Int, val y: Int) {
-        operator fun plus(other: Point) = Point(x + other.x, y + other.y)
-        operator fun minus(other: Point) = Point(x - other.x, y - other.y)
-        operator fun times(o: Int) = Point(x * o, y * o)
-
-        fun neighbours() = setOf(
-            copy(x = x + 1),
-            copy(y = y + 1),
-            copy(x = x - 1),
-            copy(y = y - 1),
-        )
-
-        companion object {
-            fun from(line: String) = line.split(',').map { it.toInt() }.let { (x, y) -> Point(x, y) }
-        }
-    }
-
-    private fun path(bytes: List<Point>): Int {
+    private fun distance(bytes: List<Point>): Int {
         val queue = PriorityQueue<Pair<Point, Int>> { a, b -> a.second.compareTo(b.second) }
         queue.add(start to 0)
         val seen = mutableSetOf<Point>()
@@ -65,7 +48,7 @@ class Day18(val input: List<String>) : Puzzle {
             if (next in seen) continue
             seen += next
             if (next == exit) return cost
-            next.neighbours()
+            next.neighbors()
                 .filter { it.x in range && it.y in range }
                 .filter { it !in bytes }
                 .forEach { queue.add(it to cost + 1) }

src/main/kotlin/days/Day4.kt

@@ -43,5 +43,4 @@ class Day4(val memory: List<String>) : Puzzle {
         return memory[y][x]
     }
 
-    data class Point(val x: Int, val y: Int)
 }

src/main/kotlin/days/Day8.kt

@@ -41,11 +41,4 @@ class Day8(val input: List<String>) : Puzzle {
         if (inBounds(next)) next else null
     }
 
-    data class Point(val x: Int, val y: Int) {
-
-        operator fun plus(other: Point) = Point(x + other.x, y + other.y)
-        operator fun minus(other: Point) = Point(x - other.x, y - other.y)
-        operator fun times(o: Int) = Point(x * o, y * o)
-    }
-
 }

src/main/kotlin/days/Geometry.kt

@@ -0,0 +1,22 @@
+package days
+
+data class Point(val x: Int, val y: Int) {
+    operator fun plus(other: Point) = Point(x + other.x, y + other.y)
+    operator fun minus(other: Point) = Point(x - other.x, y - other.y)
+    operator fun times(o: Int) = Point(x * o, y * o)
+    operator fun Int.times(p: Point) = Point(p.x * this, p.y * this)
+    operator fun List<Point>.contains(p: Point) = any { it == p }
+    fun neighbors(): List<Point> = NEIGHBORS.map { this + it }
+    fun corners() = CORNERS.map { (a, b) -> listOf(this + a, this + a + b, this + b) }
+
+    companion object {
+        private val NORTH = Point(-1, 0)
+        private val WEST = Point(0, -1)
+        private val SOUTH = Point(1, 0)
+        private val EAST = Point(0, 1)
+        val NEIGHBORS = listOf(EAST, SOUTH, WEST, NORTH)
+        val CORNERS = listOf(EAST, SOUTH, WEST, NORTH, EAST).zipWithNext()
+
+        fun from(line: String) = line.split(',').map { it.toInt() }.let { (x, y) -> Point(x, y) }
+    }
+}