用兩個棧實(shí)現(xiàn)一個隊(duì)列辽幌。隊(duì)列的聲明如下，請實(shí)現(xiàn)它的兩個函數(shù) appendTail 和 deleteHead 椿访，分別完成在隊(duì)列尾部插入整數(shù)和在隊(duì)列頭部刪除整數(shù)的功能乌企。(若隊(duì)列中沒有元素，deleteHead 操作返回 -1 )
示例 1：
輸入：
["CQueue","appendTail","deleteHead","deleteHead"]
[[],[3],[],[]]
輸出：[null,null,3,-1]
示例 2：
輸入：
["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"]
[[],[],[5],[2],[],[]]
輸出：[null,-1,null,null,5,2]
提示：
1 <= values <= 10000
最多會對 appendTail成玫、deleteHead 進(jìn)行 10000 次調(diào)用
var CQueue = function() {
this.arr = [];
};
/**
* @param {number} value
* @return {void}
*/
CQueue.prototype.appendTail = function(value) {
this.arr.push(value)
return null;
};
/**
* @return {number}
*/
CQueue.prototype.deleteHead = function() {
return this.arr.length > 0 ? this.arr.shift() : -1
};
/**
* Your CQueue object will be instantiated and called as such:
* var obj = new CQueue()
* obj.appendTail(value)
* var param_2 = obj.deleteHead()
*/
