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LeetCode 731, Medium. Topics: Array, Binary Search, Design, Segment Tree, Ordered Set, Prefix Sum. View on LeetCode. Generate this problem as a practice environment: tested reference solution, 12 parametrized pytest cases, and a playground notebook:

Problem

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

Examples

Constraints

  • 0 <= start < end <= 10^9
  • At most 1000 calls will be made to book.

Solution

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

Complexity

Tags

NeetCode All.
Last modified on September 7, 2026