lib: optimize priority queue

PR-URL: #57100
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: gurgunday

lib/internal/priority_queue.js

@@ -47,20 +47,28 @@ module.exports = class PriorityQueue {
 constsetPosition=this.#setPosition;
 constheap=this.#heap;
 constsize=this.#size;
+consthsize=size>>1;
 constitem=heap[pos];
 
-while(pos*2<=size){
-letchildIndex=pos*2+1;
-if(childIndex>size||compare(heap[pos*2],heap[childIndex])<0)
-childIndex=pos*2;
-constchild=heap[childIndex];
-if(compare(item,child)<=0)
-break;
+while(pos<=hsize){
+letchild=pos<<1;
+constnextChild=child+1;
+letchildItem=heap[child];
+
+if(nextChild<=size&&compare(heap[nextChild],childItem)<0){
+child=nextChild;
+childItem=heap[nextChild];
+}
+
+if(compare(item,childItem)<=0)break;
+
 if(setPosition!==undefined)
-setPosition(child,pos);
-heap[pos]=child;
-pos=childIndex;
+setPosition(childItem,pos);
+
+heap[pos]=childItem;
+pos=child;
 }
+
 heap[pos]=item;
 if(setPosition!==undefined)
 setPosition(item,pos);
@@ -73,27 +81,30 @@ module.exports = class PriorityQueue {
 constitem=heap[pos];
 
 while(pos>1){
-constparent=heap[pos/2|0];
-if(compare(parent,item)<=0)
+constparent=pos>>1;
+constparentItem=heap[parent];
+if(compare(parentItem,item)<=0)
 break;
-heap[pos]=parent;
+heap[pos]=parentItem;
 if(setPosition!==undefined)
-setPosition(parent,pos);
-pos=pos/2|0;
+setPosition(parentItem,pos);
+pos=parent;
 }
+
 heap[pos]=item;
 if(setPosition!==undefined)
 setPosition(item,pos);
 }
 
 removeAt(pos){
 constheap=this.#heap;
-constsize=--this.#size;
-heap[pos]=heap[size+1];
-heap[size+1]=undefined;
+letsize=this.#size;
+heap[pos]=heap[size];
+heap[size]=undefined;
+size=--this.#size;
 
 if(size>0&&pos<=size){
-if(pos>1&&this.#compare(heap[pos/2|0],heap[pos])>0)
+if(pos>1&&this.#compare(heap[pos>>1],heap[pos])>0)
 this.percolateUp(pos);
 else
 this.percolateDown(pos);