729. My Calendar I

Description

You are implementing a program to use as your calendar. We can add a new event if adding the event will not cause a double booking.

A double booking happens when two events have some non-empty intersection (i.e., some moment is common to both events.).

The event can be represented as a pair of integers start and end that represents a booking on the half-open interval [start, end), the range of real numbers x such that start <= x < end.

Implement the MyCalendar class:

• MyCalendar() Initializes the calendar object.
• boolean book(int start, int end) Returns true if the event can be added to the calendar successfully without causing a double booking. Otherwise, return false and do not add the event to the calendar.

 

Example 1:

Input
["MyCalendar", "book", "book", "book"]
[[], [10, 20], [15, 25], [20, 30]]
Output
[null, true, false, true]

Explanation
MyCalendar myCalendar = new MyCalendar();
myCalendar.book(10, 20); // return True
myCalendar.book(15, 25); // return False, It can not be booked because time 15 is already booked by another event.
myCalendar.book(20, 30); // return True, The event can be booked, as the first event takes every time less than 20, but not including 20.

 

Constraints:

• 0 <= start < end <= 109
• At most 1000 calls will be made to book.

 

Solutions

Solution: Brute Force

• Time complexity: O(n²)
• Space complexity: O(n)

 

JavaScript

const MyCalendar = function () {
  this.calendar = [];
};

/**
 * @param {number} start
 * @param {number} end
 * @return {boolean}
 */
MyCalendar.prototype.book = function (start, end) {
  for (const event of this.calendar) {
    if (end > event.start && start < event.end) return false;
  }

  this.calendar.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)
 */