dist-javascript-algorithms-and-data-structures/dist/data-structures/priority-queue/PriorityQueue.js

Algorithms and data-structures implemented on JavaScript

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;

var _MinHeap = _interopRequireDefault(require("../heap/MinHeap"));

var _Comparator = _interopRequireDefault(require("../../utils/comparator/Comparator"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

// It is the same as min heap except that when comparing to elements
// we take into account not element's value but rather its priority.
class PriorityQueue extends _MinHeap.default {
  constructor() {
    super();
    this.priorities = {};
    this.compare = new _Comparator.default(this.comparePriority.bind(this));
  }
  /**
   * @param {*} item
   * @param {number} [priority]
   * @return {PriorityQueue}
   */


  add(item, priority = 0) {
    this.priorities[item] = priority;
    super.add(item);
    return this;
  }
  /**
   * @param {*} item
   * @param {Comparator} [customFindingComparator]
   * @return {PriorityQueue}
   */


  remove(item, customFindingComparator) {
    super.remove(item, customFindingComparator);
    delete this.priorities[item];
    return this;
  }
  /**
   * @param {*} item
   * @param {number} priority
   * @return {PriorityQueue}
   */


  changePriority(item, priority) {
    this.remove(item, new _Comparator.default(this.compareValue));
    this.add(item, priority);
    return this;
  }
  /**
   * @param {*} item
   * @return {Number[]}
   */


  findByValue(item) {
    return this.find(item, new _Comparator.default(this.compareValue));
  }
  /**
   * @param {*} item
   * @return {boolean}
   */


  hasValue(item) {
    return this.findByValue(item).length > 0;
  }
  /**
   * @param {*} a
   * @param {*} b
   * @return {number}
   */


  comparePriority(a, b) {
    if (this.priorities[a] === this.priorities[b]) {
      return 0;
    }

    return this.priorities[a] < this.priorities[b] ? -1 : 1;
  }
  /**
   * @param {*} a
   * @param {*} b
   * @return {number}
   */


  compareValue(a, b) {
    if (a === b) {
      return 0;
    }

    return a < b ? -1 : 1;
  }

}

exports.default = PriorityQueue;