622.js

var MyCircularQueue = function(k) {
    this.size = k;
    this.buffer = [];
    this.front = 0;
    this.rear = -1;
};

/**
 * Insert an element into the circular queue. Return true if the operation is successful. 
 * @param {number} value
 * @return {boolean}
 */
MyCircularQueue.prototype.enQueue = function(value) {
    if(this.isFull()) return false;
    this.buffer[++this.rear] = value;
    return true;
};

/**
 * Delete an element from the circular queue. Return true if the operation is successful.
 * @return {boolean}
 */
MyCircularQueue.prototype.deQueue = function() {
    if(this.isEmpty())return false;
    this.buffer[this.front]=undefined;
    this.front++;
    return true;
};

/**
 * Get the front item from the queue.
 * @return {number}
 */
MyCircularQueue.prototype.Front = function() {
    if(this.isEmpty()) return -1;
    return this.buffer[this.front];
};

/**
 * Get the last item from the queue.
 * @return {number}
 */
MyCircularQueue.prototype.Rear = function() {
    if(this.isEmpty()) return -1;
    return this.buffer[this.rear];
};

/**
 * Checks whether the circular queue is empty or not.
 * @return {boolean}
 */
MyCircularQueue.prototype.isEmpty = function() {
    if(this.rear<this.front)return true;
    return false;
};

/**
 * Checks whether the circular queue is full or not.
 * @return {boolean}
 */
MyCircularQueue.prototype.isFull = function() {
    return this.rear-this.front+1===this.size;
};