Leetcode•Jun 13, 2025

My Calendar I

Hazrat Ali

Leetcode

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 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 MyCalendar class:

  • MyCalendar() 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 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.


Solution
class MyCalendar {
  constructor() {
    this.intervals = [];
  }

  /**
   * @param {number} start
   * @param {number} end
   * @return {boolean}
   */
  book(start, end) {
    let lo = 0;
    let hi = this.intervals.length - 1;

    while (lo <= hi) {
      const mid = lo + Math.floor((hi - lo) / 2);
      const interval = this.intervals[mid];

      if (end <= interval[0]) {
        hi = mid - 1;
      } else if (start >= interval[1]) {
        lo = mid + 1;
      } else {
        return false;
      }
    }

    this.intervals.splice(lo, 0, [start, end]);

    return true;
  }
}


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