javascript的队列，优先队列，循环队列

按书上的来弄的。慢慢理解了。

function Queue() {
    var items = [];
    this.enqueue = function(element){
        items.push(element);
    }

    this.dequeue = function(){
        return items.shift();
    }

    this.front = function(){
        return items[0];
    }

    this.isEmpty = function(){
        return items.length == 0;
    }

    this.clear = function(){
        items = [];
    }

    this.size = function(){
        return items.length;
    }

    this.print = function(){
        console.log(items.toString());
    }
}

function PriorityQueue() {
    var items = [];

    function QueueElement(element, priority){
        this.element = element;
        this.priority = priority;
    }
    this.enqueue = function(element, priority){
        var queueElement = new QueueElement(element, priority);
        if (this.isEmpty()){
            items.push(queueElement);
        } else {
            var added = false;
            for (var 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.dequeue = function(){
        return items.shift();
    }

    this.front = function(){
        return items[0];
    }

    this.isEmpty = function(){
        return items.length == 0;
    }

    this.clear = function(){
        items = [];
    }

    this.size = function(){
        return items.length;
    }

    this.print = function(){
        console.log(items);
    }
}

var priorityQueue = new PriorityQueue();
priorityQueue.enqueue("John", 2);
priorityQueue.enqueue("Jack", 1);
priorityQueue.enqueue("Camila", 1);
priorityQueue.print();

function hotPotato(nameList, num){
    var queue = new Queue();

    for (var i=0; i<nameList.length; i++){
        queue.enqueue(nameList[i]);
    }

    var eliminated = '';
    while (queue.size() > 1){
        for (var i=0; i<num; i++){
            queue.enqueue(queue.dequeue());
        }
        eliminated = queue.dequeue();
        console.log(eliminated + '在击鼓传花中被淘汰.');
    }
    return queue.dequeue();
}

var names = ['John','Jack','Camila','Ingrid','Carl'];
var winner = hotPotato(names, 7);
console.log('胜利者：' + winner);