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69 lines
1.4 KiB
69 lines
1.4 KiB
"use strict";
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const Queue = require("./Queue");
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/**
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* @class
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* @private
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*/
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class PriorityQueue {
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constructor(size) {
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this._size = Math.max(+size | 0, 1);
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/** @type {Queue[]} */
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this._slots = [];
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// initialize arrays to hold queue elements
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for (let i = 0; i < this._size; i++) {
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this._slots.push(new Queue());
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}
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}
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get length() {
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let _length = 0;
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for (let i = 0, slots = this._slots.length; i < slots; i++) {
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_length += this._slots[i].length;
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}
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return _length;
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}
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enqueue(obj, priority) {
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// Convert to integer with a default value of 0.
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priority = (priority && +priority | 0) || 0;
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if (priority) {
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if (priority < 0 || priority >= this._size) {
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priority = this._size - 1;
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// put obj at the end of the line
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}
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}
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this._slots[priority].push(obj);
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}
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dequeue() {
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for (let i = 0, sl = this._slots.length; i < sl; i += 1) {
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if (this._slots[i].length) {
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return this._slots[i].shift();
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}
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}
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return;
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}
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get head() {
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for (let i = 0, sl = this._slots.length; i < sl; i += 1) {
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if (this._slots[i].length > 0) {
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return this._slots[i].head;
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}
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}
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return;
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}
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get tail() {
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for (let i = this._slots.length - 1; i >= 0; i--) {
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if (this._slots[i].length > 0) {
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return this._slots[i].tail;
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}
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}
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return;
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}
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}
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module.exports = PriorityQueue;
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