function Queue() { //一般队列

let items = [];

this.enqueue = function(e){

items.push(e);

}

this.dequeue = function () {

return items.shift();

}

this.front = function () {

return items[0];

}

this.isEmpty = function () {

return items.length == 0;

}

this.size = function () {

return items.length;

}

this.print = function () {

console.log(items.toString());

}

}

function PriorityQueue() { //优先队列

let items = [];

function QueueElement(element, priority) {

this.element = element;

this.priority = priority;

}

this.enqueue = function(element, priority) {

let queueElement = new QueueElement(element, priority);

let added = false;

for (let i = 0; i < items.length; i++) {

if (queueElement.priority < items[i].priority) {

items.splice(i, 0, queueElement);

added = true;

break;

}

}

if (!added) {

items.push(queueElement);

}

};

this.print = function() {

for (let i = 0; i < items.length; i++) {

console.log(`${items[i].element} -

${items[i].priority}`);

}

};

}

let queue = new Queue();

queue.enqueue('Cyclone');

queue.enqueue('Joker');

queue.enqueue('Luna');

queue.enqueue('Metal');

queue.enqueue('Heat');

queue.enqueue('Trigger');

queue.dequeue();

queue.print();