From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: HaHaWTH <102713261+HaHaWTH@users.noreply.github.com>
Date: Tue, 9 Nov 2077 00:00:00 +0800
Subject: [PATCH] Smart sort entities in NearestLivingEntitySensor

Co-authored-by: Taiyou06 <kaandindar21@gmail.com>

FastBitRadix Sort will be used. (see https://ieeexplore.ieee.org/document/7822019 for more)
When entity count reached the threshold, Bucket Sort will be used.

In non-strict test, this can give ~60-110% improvement (524ms on Paper, 204ms on Leaf),
under 625 villagers situation.

diff --git a/net/minecraft/world/entity/ai/sensing/NearestLivingEntitySensor.java b/net/minecraft/world/entity/ai/sensing/NearestLivingEntitySensor.java
index b0c5e41fefc7c9adf1a61bd5b52861736657d37e..a887bb8ed2318d6ee39be350a1d0e7223ecf3ff5 100644
--- a/net/minecraft/world/entity/ai/sensing/NearestLivingEntitySensor.java
+++ b/net/minecraft/world/entity/ai/sensing/NearestLivingEntitySensor.java
@@ -13,17 +13,28 @@ import net.minecraft.world.entity.ai.memory.NearestVisibleLivingEntities;
 import net.minecraft.world.phys.AABB;
 
 public class NearestLivingEntitySensor<T extends LivingEntity> extends Sensor<T> {
+
+    // Leaf start - Smart sort entities in NearestLivingEntitySensor
+    private final org.dreeam.leaf.util.fastBitRadixSort sorter;
+    // Leaf end - Smart sort entities in NearestLivingEntitySensor
+    public NearestLivingEntitySensor() {
+        this.sorter = new org.dreeam.leaf.util.fastBitRadixSort();
+    }
+
     @Override
     protected void doTick(ServerLevel level, T entity) {
         double attributeValue = entity.getAttributeValue(Attributes.FOLLOW_RANGE);
+        double rangeSqr = attributeValue * attributeValue;
         AABB aabb = entity.getBoundingBox().inflate(attributeValue, attributeValue, attributeValue);
-        List<LivingEntity> entitiesOfClass = level.getEntitiesOfClass(
-            LivingEntity.class, aabb, matchableEntity -> matchableEntity != entity && matchableEntity.isAlive()
-        );
-        entitiesOfClass.sort(Comparator.comparingDouble(entity::distanceToSqr));
+
+        List<LivingEntity> entities = level.getEntitiesOfClass(LivingEntity.class, aabb, e -> e != entity && e.isAlive() && entity.distanceToSqr(e) <= rangeSqr);
+
+        LivingEntity[] sorted = this.sorter.sort(entities, entity, LivingEntity.class);
+        List<LivingEntity> sortedList = java.util.Arrays.asList(sorted);
+
         Brain<?> brain = entity.getBrain();
-        brain.setMemory(MemoryModuleType.NEAREST_LIVING_ENTITIES, entitiesOfClass);
-        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_LIVING_ENTITIES, new NearestVisibleLivingEntities(level, entity, entitiesOfClass));
+        brain.setMemory(MemoryModuleType.NEAREST_LIVING_ENTITIES, sortedList);
+        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_LIVING_ENTITIES, new NearestVisibleLivingEntities(level, entity, sortedList));
     }
 
     @Override