Improve year 2022 day11

Author: linl33

year2022/src/main/java/dev/linl33/adventofcode/year2022/Day11.java

@@ -1,10 +1,15 @@
 package dev.linl33.adventofcode.year2022;
 
+import jdk.incubator.vector.FloatVector;
+import jdk.incubator.vector.VectorOperators;
+import jdk.incubator.vector.VectorSpecies;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.BufferedReader;
 
 public class Day11 extends AdventSolution2022<Long, Long> {
+  private static final VectorSpecies<Float> SPECIES = FloatVector.SPECIES_PREFERRED;
+
   private static final int MAX_ITEMS = 50;
   private static final int PART_1_ROUNDS = 20;
   private static final int PART_2_ROUNDS = 10_000;
@@ -89,14 +94,19 @@ public Long part2(@NotNull BufferedReader reader) throws Exception {
     var input = reader.lines().toArray(String[]::new);
     var monkeyCount = (input.length + 1) / 7;
 
-    var items = new int[MAX_ITEMS];
+    if (monkeyCount > SPECIES.length()) {
+      // shouldn't happen, don't want to handle it
+      throw new IllegalArgumentException();
+    }
+
+    var items = new float[MAX_ITEMS];
     var itemsPosition = new int[MAX_ITEMS];
     var itemsPointer = 0;
 
-    var offsets = new int[monkeyCount * monkeyCount];
-    var multipliers = new int[monkeyCount * monkeyCount];
+    var offsets = new float[monkeyCount];
+    var multipliers = new float[monkeyCount];
 
-    var moduli = new int[monkeyCount];
+    var moduli = new float[monkeyCount];
     var trueValues = new int[monkeyCount];
     var falseValues = new int[monkeyCount];
 
@@ -121,49 +131,46 @@ public Long part2(@NotNull BufferedReader reader) throws Exception {
       var op = input[i + 2].charAt(23);
       if (op == '+') {
         var opVal = Integer.parseInt(input[i + 2], 25, input[i + 2].length(), 10);
-        offsets[m * monkeyCount] = opVal;
-        multipliers[m * monkeyCount] = 1;
+        offsets[m] = opVal;
+        multipliers[m] = 1;
       } else {
         if (input[i + 2].charAt(25) == 'o') {
           // handle new = old * old
           squareMonkey = m;
         } else {
           var opVal = Integer.parseInt(input[i + 2], 25, input[i + 2].length(), 10);
-          multipliers[m * monkeyCount] = opVal;
+          multipliers[m] = opVal;
         }
       }
     }
 
-    for (int i = 0; i < offsets.length; i++) {
-      var monkeyIndex = (i / monkeyCount) * monkeyCount;
-      var modulus = moduli[i % monkeyCount];
-      offsets[i] = offsets[monkeyIndex] % modulus;
-      multipliers[i] = multipliers[monkeyIndex] % modulus;
-    }
-
     var inspectionCounts = new int[monkeyCount];
-    var worries = new int[monkeyCount];
 
-    for (int i = 0; i < itemsPointer; i++) {
-      var item = items[i];
-      for (int m = 0; m < monkeyCount; m++) {
-        worries[m] = item % moduli[m];
-      }
+    var mask = SPECIES.indexInRange(0, monkeyCount);
+    var modV = FloatVector.fromArray(SPECIES, moduli, 0, mask);
 
+    for (int i = 0; i < itemsPointer; i++) {
+      var worriesVector = FloatVector.broadcast(SPECIES, items[i]);
       var pos = itemsPosition[i];
+
       for (int round = 0; round < PART_2_ROUNDS; round++) {
         inspectionCounts[pos]++;
-        if (pos == squareMonkey) {
-          for (int j = 0, mulIndex = squareMonkey * monkeyCount; j < monkeyCount; j++, mulIndex++) {
-            multipliers[mulIndex] = worries[j] % moduli[j];
-          }
-        }
-
-        for (int m = 0, opIndex = pos * monkeyCount; m < monkeyCount; m++, opIndex++) {
-          worries[m] = (worries[m] * multipliers[opIndex] + offsets[opIndex]) % moduli[m];
-        }
 
-        var posNext = worries[pos] == 0 ? trueValues[pos] : falseValues[pos];
+        worriesVector = worriesVector
+            .fma(
+                pos == squareMonkey ? worriesVector : FloatVector.broadcast(SPECIES, multipliers[pos]),
+                FloatVector.broadcast(SPECIES, offsets[pos])
+            );
+
+        // compute mod with using a - (a/d) * d
+        var tmp = worriesVector
+            .div(modV)
+            .convert(VectorOperators.F2I, 0)
+            .convert(VectorOperators.I2F, 0)
+            .mul(modV);
+        worriesVector = worriesVector.sub(tmp);
+
+        var posNext = worriesVector.test(VectorOperators.IS_DEFAULT).laneIsSet(pos) ? trueValues[pos] : falseValues[pos];
         if (posNext > pos) {
           round--;
         }
@@ -175,8 +182,8 @@ public Long part2(@NotNull BufferedReader reader) throws Exception {
   }
 
   private static long calculateLevel(int[] inspectionCounts) {
-    var highest = -1L;
-    var secondHighest = -1L;
+    var highest = -1;
+    var secondHighest = -1;
     for (int value : inspectionCounts) {
       if (value > secondHighest) {
         if (value < highest) {
@@ -188,6 +195,6 @@ private static long calculateLevel(int[] inspectionCounts) {
       }
     }
 
-    return highest * secondHighest;
+    return Math.multiplyFull(highest, secondHighest);
   }
 }