Meeting rooms

Given an 2D integer array A of size N x 2 denoting time intervals of different meetings.

Where:

• A[i][0] = start time of the i^th meeting.
• A[i][1] = end time of the i^th meeting.

Find the minimum number of conference rooms required so that all meetings can be done.

Note :- If a meeting ends at time t, another meeting starting at time t can use the same conference room

1 <= N <= 10⁵

0 <= A[i][0] < A[i][1] <= 2 * 10⁹

The only argument given is the matrix A.

Return the minimum number of conference rooms required so that all meetings can be done.

Input 1:

 A = [      [0, 30]
            [5, 10]
            [15, 20]
     ]

Input 2:

 A =  [     [1, 18]
            [18, 23]
            [15, 29]
            [4, 15]
            [2, 11]
            [5, 13]
      ]

Output 1:

 2

Output 2:

 4

Explanation 1:

 Meeting one can be done in conference room 1 form 0 - 30.
 Meeting two can be done in conference room 2 form 5 - 10.
 Meeting three can be done in conference room 2 form 15 - 20 as it is free in this interval.

Explanation 2:

 Meeting one can be done in conference room 1 from 1 - 18.
 Meeting five can be done in conference room 2 from 2 - 11.
 Meeting four can be done in conference room 3 from 4 - 15.
 Meeting six can be done in conference room 4 from 5 - 13.
 Meeting three can be done in conference room 2 from 15 - 29 as it is free in this interval.
 Meeting two can be done in conference room 4 from 18 - 23 as it is free in this interval.