# My Calendar III

This page explains Java solution to problem `My Calendar III`

using `TreeMap`

data structure.

## Problem Statement

Implement a `MyCalendarIii`

class to store your events. A new event can always be added.

Your class will have one method, `book(int start, int end)`

. Formally, this represents a booking on the half open interval `[start, end)`

, the range of real numbers `x`

such that `start `

A K-booking happens when K events have some non-empty intersection (ie., there is some time that is common to all `K`

events.)

For each call to the method `MyCalendar.book`

, return an integer `K`

representing the largest integer such that there exists a K-booking in the calendar.

**Example 1:****Input**:

MyCalendarThree();

MyCalendarThree.book(10, 20); // returns 1

MyCalendarThree.book(50, 60); // returns 1

MyCalendarThree.book(10, 40); // returns 2

MyCalendarThree.book(5, 15); // returns 3

MyCalendarThree.book(5, 10); // returns 3

MyCalendarThree.book(25, 55); // returns 3

**Explanation**:

The first two events can be booked and are disjoint, so the maximum K-booking is a 1-booking.

The third event [10, 40) intersects the first event, and the maximum K-booking is a 2-booking.

The remaining events cause the maximum K-booking to be only a 3-booking.

Note that the last event locally causes a 2-booking, but the answer is still 3 because

eg. [10, 20), [10, 40), and [5, 15) are still triple booked.

**Example 2:****Input**: A = [1,2], B = [3,4]

**Output**: 2.50000

**Explanation**: merged array = [1,2,3,4] and median is (2 + 3) / 2 = 2.5

## Solution

If you have any suggestions in below code, please

create a pull request by clicking here.

```
package com.vc.hard;
import java.util.*;
class MyCalendarIii {
private TreeMap<Integer, Integer> map;
public MyCalendarIii() {
map = new TreeMap<>();
}
public int book(int start, int end) {
map.put(start, map.getOrDefault(start, 0) + 1);
map.put(end, map.getOrDefault(end, 0) - 1);
int ongoing = 0;
int res = 0;
for(Map.Entry<Integer, Integer> entry: map.entrySet()) {
ongoing += entry.getValue();
res = Math.max(ongoing, res);
}
return res;
}
}
/**
* Your MyCalendarThree object will be instantiated and called as such:
* MyCalendarIii obj = new MyCalendarIii();
* int param_1 = obj.book(start,end);
*/
```

## Time Complexity

O(N^{2}) Where

N is total number of bookings

## Space Complexity

O(N) Where

N is total number of bookings