队列的最大值

[lzxjack]

No description provided.

[lxy-Jason]

var MaxQueue = function() {
    this.arr = []
    this.maxArr = [] //这里要用一个数组,是因为pop可能会把最大数给删除
};

/**
 * @return {number}
 */
MaxQueue.prototype.max_value = function() {
    return this.arr.length ? this.maxArr[0] : -1
};

/** 
 * @param {number} value
 * @return {void}
 */
MaxQueue.prototype.push_back = function(value) {
    this.arr.push(value) 
    while(this.maxArr.length && this.maxArr[this.maxArr.length - 1] < value){
        this.maxArr.pop() //比push进来的数小的,可以直接删除,因为这是队列
    }
    this.maxArr.push(value)
};

/**
 * @return {number}
 */
MaxQueue.prototype.pop_front = function() {
    if(!this.arr.length) return -1
    const temp = this.arr.shift();
    if(temp === this.maxArr[0]){
        this.maxArr.shift()
    }
    return temp
};

/**
 * Your MaxQueue object will be instantiated and called as such:
 * var obj = new MaxQueue()
 * var param_1 = obj.max_value()
 * obj.push_back(value)
 * var param_3 = obj.pop_front()
 */