Grokking the Coding Interview: Patterns for Coding Questions

Problem Challenge 1: Minimum Meeting Rooms (hard)

## Problem Statement

Given a list of intervals representing the start and end time of ‘N’ meetings, find the **minimum number of rooms** required to **hold all the meetings**.

**Example 1**:
```
Meetings: [[1,4], [2,5], [7,9]]
Output: 2
Explanation: Since [1,4] and [2,5] overlap, we need two rooms to hold these two meetings. [7,9] can occur in any of the two rooms later.
```

**Example 2**:
```
Meetings: [[6,7], [2,4], [8,12]]
Output: 1
Explanation: None of the meetings overlap, therefore we only need one room to hold all meetings.
```

**Example 3**:
```
Meetings: [[1,4], [2,3], [3,6]]