Algorithm
Problem Name: 731. My Calendar II
Problem Link: https://leetcode.com/problems/my-calendar-ii/
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 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 MyCalendarTwo class:
MyCalendarTwo()Initializes the calendar object.boolean book(int start, int end)Returnstrueif the event can be added to the calendar successfully without causing a triple booking. Otherwise, returnfalseand 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.
Constraints:
0 <= start < end <= 109- At most
1000calls will be made tobook.
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
class MyCalendarTwo {
private TreeMap delta;
public MyCalendarTwo() {
this.delta = new TreeMap < >();
}
public boolean book(int start, int end) {
delta.put(start, delta.getOrDefault(start, 0) + 1);
delta.put(end, delta.getOrDefault(end, 0) - 1);
int active = 0;
for (int d : delta.values()) {
active += d;
if (active >= 3) {
delta.put(start, delta.get(start) - 1);
delta.put(end, delta.get(end) + 1);
return false;
}
}
return true;
}
}
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]
#2 Code Example with Javascript Programming
Code -
Javascript Programming
const MyCalendarTwo = function () {
this.calendar = []
this.overlaps = []
}
MyCalendarTwo.prototype.book = function (start, end) {
for (let i = 0; i < this.overlaps.length; i++) {
if (start < this.overlaps[i].end && end > this.overlaps[i].start)
return false
}
for (let i = 0; i < this.calendar.length; i++) {
if (start < this.calendar[i].end && end > this.calendar[i].start)
this.overlaps.push({
start: Math.max(start, this.calendar[i].start),
end: Math.min(end, this.calendar[i].end),
})
}
this.calendar.push({ start: start, end: end })
return true
}
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]
#3 Code Example with Python Programming
Code -
Python Programming
class MyCalendarTwo:
def __init__(self):
self.overlaps = []
self.calendar = []
def book(self, start, end):
for i, j in self.overlaps:
if start < j and end > i:
return False
for i, j in self.calendar:
if start < j and end > i:
self.overlaps.append((max(start, i), min(end, j)))
self.calendar.append((start, end))
return True
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]