Merge Intervals

Given a list of intervals where each is [start, end], merge every group of overlapping intervals and return the resulting non-overlapping intervals. Intervals that touch ([1,4] and [4,5]) overlap.

Return the intervals in any order.

Example 1

Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]

[1,3] and [2,6] overlap, so they become [1,6].

Example 2

Input: intervals = [[1,4],[4,5]]
Output: [[1,5]]

Example 3

Input: intervals = [[4,7],[1,4]]
Output: [[1,7]]

The input is not necessarily sorted.

Constraints

• 1 <= intervals.length <= 10^5
• 0 <= start <= end <= 10^5