Grokking the Coding Interview: Patterns for Coding Questions

Merge Intervals (medium)

## Problem Statement

Given a list of intervals, **merge all the overlapping intervals** to produce a list that has only mutually exclusive intervals.

**Example 1**:

```
Intervals: [[1,4], [2,5], [7,9]]
Output: [[1,5], [7,9]]
Explanation: Since the first two intervals [1,4] and [2,5] overlap, we merged them into one [1,5].
```

**Example 2**:
```
Intervals: [[6,7], [2,4], [5,9]]
Output: [[2,4], [5,9]]
Explanation: Since the intervals [6,7] and [5,9] overlap, we merged them into one [5,9].
```

**Example 3**:
```
Intervals: [[1,4], [2,6], [3,5]]
Output: [[1,6]]