reorg day 12

codeforkjeff · codeforkjeff · commit d632fc7f3d71 · 2018-12-15T13:25:43.000-08:00
diff --git a/src/main/scala/org/codefork/aoc2018/Day12.scala b/src/main/scala/org/codefork/aoc2018/Day12.scala
@@ -0,0 +1,77 @@
+package org.codefork.aoc2018
+
+import scala.io.Source
+
+object Day12 {
+
+  def getInput: Pots = {
+
+    val url = getClass.getResource("/day12/input.txt")
+
+    val lines = Source.fromURL(url).getLines().toSeq
+
+    lines.head
+      .replace("initial state: ", "")
+      .zipWithIndex
+      .foldLeft(Set[Int]()) {
+        case (acc, (char, index)) => {
+          acc ++ (if (char == '#') Set(index) else Set.empty)
+        }
+      }
+
+    val initial = lines.head.replace("initial state: ", "")
+    val rules = lines
+      .drop(2)
+      .map(line => line.substring(0, 5) -> line.last.toString)
+      .toMap
+
+    Pots(initial, 0, rules)
+  }
+
+  case class Pots(state: String,
+                  startingPotNumber: Int,
+                  rules: Map[String, String]) {
+
+    val padded = "...." + state + "...."
+
+    def trimTrailingPeriods(s: String) = s.reverse.dropWhile(_ == '.').reverse
+
+    def nextGenForPot(paddedPos: Int) = {
+      val slice = padded.substring(paddedPos - 2, paddedPos + 3)
+      val result =
+        if (rules.contains(slice))
+          rules(slice)
+        else "."
+      result
+    }
+
+    def nextGen = {
+      // result of next gen will be have 4 slots than padded
+      val t1 = 2
+        .to(padded.size - 3)
+        .map(paddedPos => nextGenForPot(paddedPos))
+        .mkString
+      val t2 = t1.dropWhile(ch => ch == '.')
+      val newStartingPotNumber = startingPotNumber - 2 + (t1.length - t2.length)
+      val t3 = trimTrailingPeriods(t2)
+      copy(state = t3, startingPotNumber = newStartingPotNumber)
+    }
+
+    def sumPotNumbers =
+      state
+        .foldLeft((startingPotNumber, 0)) {
+          case ((potNumber, acc), char) => {
+            val newAcc = acc + (if (char == '#') potNumber else 0)
+            (potNumber + 1, newAcc)
+          }
+        }
+        ._2
+
+    def sumPotNumbersAtGeneration(i: Int) = {
+      val result = 1.to(i).foldLeft(this)((pots, i) => pots.nextGen)
+      result.sumPotNumbers
+    }
+
+  }
+
+}
diff --git a/src/main/scala/org/codefork/aoc2018/Day12Part1.scala b/src/main/scala/org/codefork/aoc2018/Day12Part1.scala
@@ -1,66 +1,9 @@
 package org.codefork.aoc2018
 
-import scala.io.Source
-
 object Day12Part1 extends Part {
 
-  def nextGen(state: String, pos: Int, rules: Map[String, String]) = {
-    val slice = state.substring(pos - 2, pos + 3)
-    val result =
-      if (rules.contains(slice))
-        rules(slice)
-      else "."
-    result
-  }
-
-  def trimTrailingPeriods(s: String) = s.reverse.dropWhile(_ == '.').reverse
-
   override def answer: String = {
-    val url = getClass.getResource("/day12/input.txt")
-
-    val lines = Source.fromURL(url).getLines().toSeq
-
-    lines.head
-      .replace("initial state: ", "")
-      .zipWithIndex
-      .foldLeft(Set[Int]()) {
-        case (acc, (char, index)) => {
-          acc ++ (if (char == "#") Set(index) else Set.empty)
-        }
-      }
-
-    val initial = lines.head.replace("initial state: ", "")
-    val rules = lines
-      .drop(2)
-      .map(line => line.substring(0, 5) -> line.last.toString)
-      .toMap
-
-    val result = 1.to(20).foldLeft((0, initial)) { case ((startingPotNumberOfState, state), i) =>
-      {
-        val padded = "...." + state + "...."
-        // result of next gen will be have 4 slots than padded
-        val t1 = 2
-          .to(padded.size - 3)
-          .map(pos => {
-            nextGen(padded, pos, rules)
-          })
-          .mkString
-        val t2 = t1.dropWhile(ch => ch == '.')
-        val newStartingPotNumberOfState = startingPotNumberOfState - 2 + (t1.length - t2.length)
-        val t3 = trimTrailingPeriods(t2)
-        //println(i, (newStartingPotNumberOfState, t3))
-        (newStartingPotNumberOfState, t3)
-      }
-    }
-
-    val count = result._2.foldLeft((result._1, 0)) {
-      case ((potNumber, acc), char) => {
-        val newAcc = acc + (if (char == '#') potNumber else 0)
-        (potNumber + 1, newAcc)
-      }
-    }
-
-    count._2.toString
+    Day12.getInput.sumPotNumbersAtGeneration(20).toString
   }
 
 }
