My calendar i

/*
 * 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 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.
 * Constraints:
 * 0 <= start < end <= 109
 * At most 1000 calls will be made to book.

 * struct MyCalendar {

 * }


 * /** 
 *  * `&self` means the method takes an immutable reference.
 *  * If you need a mutable reference, change it to `&mut self` instead.
 *  */
 * impl MyCalendar {

 *     fn new() -> Self {

 *     }

 *     fn book(&self, start_time: i32, end_time: i32) -> bool {

 *     }
 * }
 */
struct MyCalendar {
  intervals: Vec<(i32, i32)>,
}

impl MyCalendar {
  fn new() -> Self {
    MyCalendar { intervals: Vec::new() }
  }

  fn book(&mut self, start: i32, end: i32) -> bool {
    for &(s, e) in &self.intervals {
      if start < e && end > s {
        return false;
      }
    }
    self.intervals.push((start, end));
    true
  }
}