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109 lines
2.6 KiB
109 lines
2.6 KiB
/**
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* File: array_queue.js
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* Created Time: 2022-12-13
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* Author: S-N-O-R-L-A-X (snorlax.xu@outlook.com)
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*/
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/* 基于环形数组实现的队列 */
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class ArrayQueue {
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#nums; // 用于存储队列元素的数组
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#front = 0; // 队首指针，指向队首元素
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#queSize = 0; // 队列长度
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constructor(capacity) {
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this.#nums = new Array(capacity);
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}
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/* 获取队列的容量 */
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get capacity() {
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return this.#nums.length;
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}
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/* 获取队列的长度 */
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get size() {
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return this.#queSize;
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}
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/* 判断队列是否为空 */
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empty() {
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return this.#queSize == 0;
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}
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/* 入队 */
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push(num) {
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if (this.size == this.capacity) {
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console.log("队列已满");
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return;
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}
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// 计算尾指针，指向队尾索引 + 1
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// 通过取余操作，实现 rear 越过数组尾部后回到头部
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const rear = (this.#front + this.size) % this.capacity;
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// 将 num 添加至队尾
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this.#nums[rear] = num;
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this.#queSize++;
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}
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/* 出队 */
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poll() {
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const num = this.peek();
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// 队首指针向后移动一位，若越过尾部则返回到数组头部
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this.#front = (this.#front + 1) % this.capacity;
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this.#queSize--;
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return num;
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}
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/* 访问队首元素 */
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peek() {
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if (this.empty())
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throw new Error("队列为空");
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return this.#nums[this.#front];
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}
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/* 返回 Array */
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toArray() {
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// 仅转换有效长度范围内的列表元素
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const arr = new Array(this.size);
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for (let i = 0, j = this.#front; i < this.size; i++, j++) {
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arr[i] = this.#nums[j % this.capacity];
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}
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return arr;
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}
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}
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/* Driver Code */
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/* 初始化队列 */
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const capacity = 10;
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const queue = new ArrayQueue(capacity);
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/* 元素入队 */
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queue.push(1);
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queue.push(3);
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queue.push(2);
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queue.push(5);
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queue.push(4);
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console.log("队列 queue =", queue.toArray());
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/* 访问队首元素 */
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const peek = queue.peek();
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console.log("队首元素 peek = " + peek);
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/* 元素出队 */
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const poll = queue.poll();
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console.log("出队元素 poll = " + poll + "，出队后 queue =", queue.toArray());
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/* 获取队列的长度 */
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const size = queue.size;
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console.log("队列长度 size = " + size);
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/* 判断队列是否为空 */
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const empty = queue.empty();
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console.log("队列是否为空 = " + empty);
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/* 测试环形数组 */
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for (let i = 0; i < 10; i++) {
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queue.push(i);
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queue.poll();
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console.log("第 " + i + " 轮入队 + 出队后 queue =", queue.toArray());
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}
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