729-my-calendar-i

var MyCalendar = function() {
    this.data = [];
};

/**
 * @param {number} start
 * @param {number} end
 * @return {boolean}
 */
MyCalendar.prototype.book = function(start, end) {
    for( let [L,R] of this.data){
        if(L < end && R > start){
            return false;
        }
    }
    this.data.push([start,end]);
    return true;
};

/**
 * Your MyCalendar object will be instantiated and called as such:
 * var obj = new MyCalendar()
 * var param_1 = obj.book(start,end)
 */