JavaScript 中的優先順序佇列


在本文中,我們將討論 JavaScript 中的優先佇列資料結構。

優先佇列是一種抽象資料型別(ADT),類似於常規佇列或棧資料結構,但除此之外,每個元素都與一個“優先順序”相關聯。在優先佇列中,高優先順序的元素在低優先順序的元素之前得到處理。如果兩個元素具有相同的優先順序,則按照它們在佇列中的順序進行處理。

示例 1

以下示例演示了 JavaScript 中的優先佇列類資料結構。

在這裡,我們根據元素的優先順序將元素插入佇列。在建立一個非空佇列之後,我們可以移除具有最高優先順序的元素(透過使用 shift() 方法返回前端元素)。

<!DOCTYPE html>
<html lang="en">
   <head>
      <meta charset="UTF-8" />
      <meta http-equiv="X-UA-Compatible" content="IE=edge" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0" />
      <title>PriorityQueue Data Structure</title>
   </head>
   <body>
      <script type="text/javascript">
         class QueueElement {
            constructor(elem, priNo) {
            this.element = elem;
            this.priority = priNo;
            }
         }
         class PriorityQueue {
            constructor() {
               this.queArr = [];
            }
            enqueue(elem, priNo) {
               let queueElem = new QueueElement(elem, priNo);
               let contain = false;
               for (let i = 0; i < this.queArr.length; i++) {
                  if (this.queArr[i].priority > queueElem.priority) {
                     this.queArr.splice(i, 0, queueElem);
                     contain = true;
                     break;
                  }
               }
               if (!contain) {
                  this.queArr.push(queueElem);
               }
            }
            dequeue() {
               document.write(
                  "</br>The dequeued element in the priority queue is : "
               );
               if (this.isEmpty()) return "Underflow";
               return this.queArr.shift();
            }
            front() {
               if (this.isEmpty()) return "No elements in Queue";
               return this.queArr[0];
            }
            rear() {
               document.write("</br>The rear element of the priority queue is : ");
               if (this.isEmpty()) return "The Queue is Empty..!";
               return this.queArr[this.queArr.length - 1];
            }
            isEmpty() {
               return this.queArr.length == 0;
            }
            display() {
               document.write("The Elements in the priority queue are : </br>");
               let res_Str = "";
               for (let i = 0; i < this.queArr.length; i++)
               res_Str += this.queArr[i].element + " ";
               return res_Str;
            }
         }
         var priorityQueue = new PriorityQueue();
         priorityQueue.enqueue("Alice", 2);
         priorityQueue.enqueue("Cullen", 4);
         priorityQueue.enqueue("Edward", 1);
         priorityQueue.enqueue("Bella", 2);
         priorityQueue.enqueue("Jacob", 3);
         document.write(priorityQueue.display());
      </script>
   </body>
</html>

示例 2

以下示例演示了 JavaScript 中優先佇列類資料結構的實現。

<!DOCTYPE html>
<html lang="en">
   <head>
      <meta charset="UTF-8" />
      <meta http-equiv="X-UA-Compatible" content="IE=edge" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0" />
      <title>PriorityQueue Data Structure</title>
   </head>
   <body>
      <script type="text/javascript">
         class QueueElement {
            constructor(elem, priNo) {
            this.element = elem;
            this.priority = priNo;
            }
         }
         class PriorityQueue {
            constructor() {
               this.queArr = [];
            }
            enqueue(elem, priNo) {
               let queueElem = new QueueElement(elem, priNo);
               let contain = false;
               for (let i = 0; i < this.queArr.length; i++) {
                  if (this.queArr[i].priority > queueElem.priority) {
                     this.queArr.splice(i, 0, queueElem);
                     contain = true;
                     break;
                  }
               }
               if (!contain) {
                  this.queArr.push(queueElem);
               }
            }
            dequeue() {
               document.write(
                  "</br>The dequeued element in the priority queue is : "
               );
               if (this.isEmpty()) return "Underflow";
               return this.queArr.shift();
            }
            front() {
               document.write("</br>The front element of the priority queue is : ");
               if (this.isEmpty()) return "The Queue is Empty..!";
               return this.queArr[0];
            }
            rear() {
               document.write("</br>The rear element of the priority queue is : ");
               if (this.isEmpty()) return "The Queue is Empty..!";
               return this.queArr[this.queArr.length - 1];
            }
            isEmpty() {
               return this.queArr.length == 0;
            }
            display() {
               document.write("The Elements in the priority queue are : </br>");
               let res_Str = "";
               for (let i = 0; i < this.queArr.length; i++)
               res_Str += this.queArr[i].element + " ";
               return res_Str;
            }
         }
         var priorityQueue = new PriorityQueue();
         priorityQueue.enqueue("Alice", 2);
         priorityQueue.enqueue("Cullen", 4);
         priorityQueue.enqueue("Edward", 1);
         priorityQueue.enqueue("Bella", 2);
         priorityQueue.enqueue("Jacob", 3);
         document.write(priorityQueue.display());
         document.write(priorityQueue.front().element);
         document.write(priorityQueue.rear().element);
      </script>
   </body>
</html>

更新於:2022 年 12 月 16 日

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