设置循环双端队列

题目描述：

代码实现：

• 利用数组实现

/**
 * Initialize your data structure here. Set the size of the deque to be k.
 * @param {number} k
 */
var MyCircularDeque = function(k) {
    this.arr = []
    this.size = 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.size === this.arr.length) {
        return false
    } else {
        this.arr.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.size === this.arr.length) {
        return false
    } else {
        this.arr.push(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.arr.length === 0) {
        return false
    } else {
        this.arr.shift()
        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.arr.length === 0) {
        return false
    } else {
        this.arr.pop()
        return true
    }
};
/**
 * Get the front item from the deque.
 * @return {number}
 */
MyCircularDeque.prototype.getFront = function() {
    if (this.arr.length === 0) {
        return -1
    } else {
        return this.arr[0]
    }
};
/**
 * Get the last item from the deque.
 * @return {number}
 */
MyCircularDeque.prototype.getRear = function() {
    if (this.arr.length === 0) {
        return -1
    } else {
        return this.arr[this.arr.length - 1]
    }
};
/**
 * Checks whether the circular deque is empty or not.
 * @return {boolean}
 */
MyCircularDeque.prototype.isEmpty = function() {
    if (this.arr.length === 0) {
        return true
    }
    return false
};
/**
 * Checks whether the circular deque is full or not.
 * @return {boolean}
 */
MyCircularDeque.prototype.isFull = function() {
    if (this.size === this.arr.length) {
        return true
    }
    return false
};
/**
 * Your MyCircularDeque object will be instantiated and called as such:
 * var obj = new MyCircularDeque(k)
 * var param_1 = obj.insertFront(value)
 * var param_2 = obj.insertLast(value)
 * var param_3 = obj.deleteFront()
 * var param_4 = obj.deleteLast()
 * var param_5 = obj.getFront()
 * var param_6 = obj.getRear()
 * var param_7 = obj.isEmpty()
 * var param_8 = obj.isFull()
 */