Solve 2023 day 14 part 2

src/main/scala/eu/sim642/adventofcode2023/Day14.scala

@@ -1,7 +1,7 @@
 package eu.sim642.adventofcode2023
 
 import eu.sim642.adventofcodelib.Grid
-import eu.sim642.adventofcodelib.cycle.NaiveCycleFinder
+import eu.sim642.adventofcodelib.cycle.{NaiveCycleFinder, NaiverCycleFinder}
 
 object Day14 {
 
@@ -87,12 +87,39 @@ object Day14 {
       .sum
   }
 
+  def rollNorth(grid: Grid[Char]): Grid[Char] = grid.transpose.map(rollColumn).transpose
+  def rollWest(grid: Grid[Char]): Grid[Char] = grid.map(rollColumn)
+  def rollSouth(grid: Grid[Char]): Grid[Char] = rollNorth(grid.reverse).reverse
+  def rollEast(grid: Grid[Char]): Grid[Char] = rollWest(grid.map(_.reverse)).map(_.reverse)
+
+  def rollCycle(grid: Grid[Char]): Grid[Char] =
+    rollEast(rollSouth(rollWest(rollNorth(grid))))
+
+  def rollCycles(grid: Grid[Char], cycles: Long = 1000000000L): Grid[Char] = {
+    val cycle = NaiverCycleFinder.find(grid, rollCycle)
+    // TODO: Long cycle indexing
+    //cycle(cycles)
+    val shortI = (cycles - cycle.stemLength) % cycle.cycleLength
+    cycle(cycle.stemLength + shortI.toInt)
+  }
+
+  def totalLoad2(grid: Grid[Char], cycles: Long = 1000000000L): Int = {
+    rollCycles(grid, cycles)
+      .transpose
+      .map(_.reverse.zipWithIndex.map({
+        case ('O', i) => i + 1
+        case _ => 0
+      }).sum)
+      .sum
+  }
+
 
   def parseGrid(input: String): Grid[Char] = input.linesIterator.map(_.toVector).toVector
 
   lazy val input: String = scala.io.Source.fromInputStream(getClass.getResourceAsStream("day14.txt")).mkString.trim
 
   def main(args: Array[String]): Unit = {
     println(totalLoad(parseGrid(input)))
+    println(totalLoad2(parseGrid(input)))
   }
 }

src/test/scala/eu/sim642/adventofcode2023/Day14Test.scala

@@ -24,4 +24,12 @@ class Day14Test extends AnyFunSuite {
   test("Part 1 input answer") {
     assert(totalLoad(parseGrid(input)) == 112048)
   }
+
+  test("Part 2 examples") {
+    assert(totalLoad2(parseGrid(exampleInput)) == 64)
+  }
+
+  test("Part 2 input answer") {
+    assert(totalLoad2(parseGrid(input)) == 105606)
+  }
 }