Leetcode•Jul 29, 2025

My Calendar II

Hazrat Ali

Leetcode

A triple booking happens when three events have some non-empty intersection (i.e., some moment is common to all the three events.).

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

Implement the MyCalendarTwo class:

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

 

Example 1:

Input
["MyCalendarTwo", "book", "book", "book", "book", "book", "book"]
[[], [10, 20], [50, 60], [10, 40], [5, 15], [5, 10], [25, 55]]
Output
[null, true, true, true, false, true, true]

Explanation
MyCalendarTwo myCalendarTwo = new MyCalendarTwo();
myCalendarTwo.book(10, 20); // return True, The event can be booked. 
myCalendarTwo.book(50, 60); // return True, The event can be booked. 
myCalendarTwo.book(10, 40); // return True, The event can be double booked. 
myCalendarTwo.book(5, 15);  // return False, The event cannot be booked, because it would result in a triple booking.
myCalendarTwo.book(5, 10); // return True, The event can be booked, as it does not use time 10 which is already double booked.
myCalendarTwo.book(25, 55); // return True, The event can be booked, as the time in [25, 40) will be double booked with the third event, the time [40, 50) will be single booked, and the time [50, 55) will be double booked with the second event.

Solution
class MyCalendarTwo {
  constructor() {
    this.calendar = [];
    this.overlaps = [];
  }

  /**
   * @param {number} start
   * @param {number} end
   * @return {boolean}
   */
  book(start, end) {
    for (let interval of this.overlaps) {
      if (interval[0] < end && start < interval[1]) {
        return false;
      }
    }

    for (let interval of this.calendar) {
      if (interval[0] < end && start < interval[1]) {
        this.overlaps.push([Math.max(start, interval[0]), Math.min(end, interval[1])]);
      }
    }

    this.calendar.push([start, end]);

    return true;
  }
}







Comments