107 lines
2.7 KiB
JavaScript
107 lines
2.7 KiB
JavaScript
/**
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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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/* Queue class based on circular array */
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class ArrayQueue {
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#nums; // Array for storing queue elements
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#front = 0; // Front pointer, pointing to the front element
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#queSize = 0; // Queue length
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constructor(capacity) {
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this.#nums = new Array(capacity);
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}
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/* Get the capacity of the queue */
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get capacity() {
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return this.#nums.length;
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}
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/* Get the length of the queue */
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get size() {
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return this.#queSize;
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}
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/* Determine if the queue is empty */
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isEmpty() {
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return this.#queSize === 0;
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}
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/* Enqueue */
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push(num) {
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if (this.size === this.capacity) {
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console.log('Queue is full');
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return;
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}
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// Calculate rear pointer, pointing to rear index + 1
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// Use modulo operation to wrap the rear pointer from the end of the array back to the start
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const rear = (this.#front + this.size) % this.capacity;
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// Add num to the rear
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this.#nums[rear] = num;
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this.#queSize++;
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}
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/* Dequeue */
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pop() {
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const num = this.peek();
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// Move front pointer one position backward, returning to the head of the array if it exceeds the tail
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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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/* Access front element */
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peek() {
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if (this.isEmpty()) throw new Error('Queue is empty');
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return this.#nums[this.#front];
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}
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/* Return Array */
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toArray() {
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// Only convert elements within valid length range
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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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/* Initialize queue */
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const capacity = 10;
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const queue = new ArrayQueue(capacity);
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/* Element enqueue */
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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('Queue queue =', queue.toArray());
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/* Access front element */
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const peek = queue.peek();
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console.log('Front element peek =' + peek);
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/* Element dequeue */
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const pop = queue.pop();
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console.log('Element dequeued, pop = ' + pop + ', after deque = ', queue.toArray());
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/* Get the length of the queue */
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const size = queue.size;
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console.log('Length of the queue size =' + size);
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/* Determine if the queue is empty */
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const isEmpty = queue.isEmpty();
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console.log('Is the queue empty =' + isEmpty);
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/* Test circular array */
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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('After the ' + i + 'th round of enqueueing + dequeuing, queue = ', queue.toArray());
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}
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