Design_Circular_Deque.js

/*
Design Circular Deque
https://leetcode.com/problems/design-circular-deque/description/

Design your implementation of the circular double-ended queue (deque).

Your implementation should support following operations:

MyCircularDeque(k): Constructor, set the size of the deque to be k.
insertFront(): Adds an item at the front of Deque. Return true if the operation is successful.
insertLast(): Adds an item at the rear of Deque. Return true if the operation is successful.
deleteFront(): Deletes an item from the front of Deque. Return true if the operation is successful.
deleteLast(): Deletes an item from the rear of Deque. Return true if the operation is successful.
getFront(): Gets the front item from the Deque. If the deque is empty, return -1.
getRear(): Gets the last item from Deque. If the deque is empty, return -1.
isEmpty(): Checks whether Deque is empty or not. 
isFull(): Checks whether Deque is full or not.

Example:

MyCircularDeque circularDeque = new MycircularDeque(3); // set the size to be 3
circularDeque.insertLast(1);			// return true
circularDeque.insertLast(2);			// return true
circularDeque.insertFront(3);			// return true
circularDeque.insertFront(4);			// return false, the queue is full
circularDeque.getRear();  			// return 2
circularDeque.isFull();				// return true
circularDeque.deleteLast();			// return true
circularDeque.insertFront(4);			// return true
circularDeque.getFront();			// return 4

Note:

All values will be in the range of [0, 1000].
The number of operations will be in the range of [1, 1000].
Please do not use the built-in Deque library.
*/

/**
 * Initialize your data structure here. Set the size of the deque to be k.
 * @param {number} k
 */
var MyCircularDeque = function(k) {
  this.queue = [];
  this.maxSize = k;
};

/**
* Adds an item at the front of Deque. Return true if the operation is successful. 
* @param {number} value
* @return {boolean}
*/
MyCircularDeque.prototype.insertFront = function(value) {
  if(this.isFull())
    return false;
  
  this.queue.unshift(value); 
  return true;
};

/**
* Adds an item at the rear of Deque. Return true if the operation is successful. 
* @param {number} value
* @return {boolean}
*/
MyCircularDeque.prototype.insertLast = function(value) {
  if(this.isFull())
    return false;
  
  this.queue[this.queue.length] = value;
  return true;
};

/**
* Deletes an item from the front of Deque. Return true if the operation is successful.
* @return {boolean}
*/
MyCircularDeque.prototype.deleteFront = function() {
  if(this.isEmpty())
    return false;
  
  this.queue.shift(1);
  return true;
};

/**
* Deletes an item from the rear of Deque. Return true if the operation is successful.
* @return {boolean}
*/
MyCircularDeque.prototype.deleteLast = function() {
  if(this.isEmpty())
    return false;
  
  this.queue.splice(this.queue.length - 1, 1);
  return true;
};

/**
* Get the front item from the deque.
* @return {number}
*/
MyCircularDeque.prototype.getFront = function() {
 if(this.isEmpty())
    return -1;
  return this.queue[0];
};

/**
* Get the last item from the deque.
* @return {number}
*/
MyCircularDeque.prototype.getRear = function() {
  if(this.isEmpty())
    return -1;
  return this.queue[this.queue.length - 1];
};

/**
* Checks whether the circular deque is empty or not.
* @return {boolean}
*/
MyCircularDeque.prototype.isEmpty = function() {
  return this.queue.length === 0;
};

/**
* Checks whether the circular deque is full or not.
* @return {boolean}
*/
MyCircularDeque.prototype.isFull = function() {
  return this.queue.length === this.maxSize;
};

module.exports.MyCircularDeque = MyCircularDeque;