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107 lines
2.6 KiB
107 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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/* 基於環形陣列實現的佇列 */
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class ArrayQueue {
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#nums; // 用於儲存佇列元素的陣列
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#front = 0; // 佇列首指標，指向佇列首元素
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#queSize = 0; // 佇列長度
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constructor(capacity) {
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this.#nums = new Array(capacity);
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}
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/* 獲取佇列的容量 */
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get capacity() {
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return this.#nums.length;
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}
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/* 獲取佇列的長度 */
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get size() {
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return this.#queSize;
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}
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/* 判斷佇列是否為空 */
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isEmpty() {
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return this.#queSize === 0;
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}
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/* 入列 */
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push(num) {
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if (this.size === this.capacity) {
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console.log('佇列已滿');
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return;
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}
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// 計算佇列尾指標，指向佇列尾索引 + 1
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// 透過取餘操作實現 rear 越過陣列尾部後回到頭部
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const rear = (this.#front + this.size) % this.capacity;
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// 將 num 新增至佇列尾
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this.#nums[rear] = num;
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this.#queSize++;
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}
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/* 出列 */
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pop() {
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const num = this.peek();
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// 佇列首指標向後移動一位，若越過尾部，則返回到陣列頭部
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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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/* 訪問佇列首元素 */
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peek() {
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if (this.isEmpty()) throw new Error('佇列為空');
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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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// 僅轉換有效長度範圍內的串列元素
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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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/* 初始化佇列 */
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const capacity = 10;
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const queue = new ArrayQueue(capacity);
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/* 元素入列 */
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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('佇列 queue =', queue.toArray());
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/* 訪問佇列首元素 */
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const peek = queue.peek();
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console.log('佇列首元素 peek = ' + peek);
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/* 元素出列 */
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const pop = queue.pop();
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console.log('出列元素 pop = ' + pop + '，出列後 queue =', queue.toArray());
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/* 獲取佇列的長度 */
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const size = queue.size;
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console.log('佇列長度 size = ' + size);
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/* 判斷佇列是否為空 */
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const isEmpty = queue.isEmpty();
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console.log('佇列是否為空 = ' + isEmpty);
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/* 測試環形陣列 */
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for (let i = 0; i < 10; i++) {
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queue.push(i);
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queue.pop();
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console.log('第 ' + i + ' 輪入列 + 出列後 queue =', queue.toArray());
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}
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