We are given an array of closed intervalsclosedintervals called intervals, where each interval has a start time and an end time and is represented as intervals[i] = [starti, endi]. Your task is to merge all the overlapping intervalsOverlapping intervals are two or more intervals with at least one common point in time. and return an array of the resulting non-overlapping intervals that cover all the intervals in the input.

Constraints:

• $1 \leq$ intervals.length $\leq10^3$

• intervals[i].length $== 2$

• $0\leq$ starti $\leq$ endi $\le$ ...