Merge Intervals

Given a collection of intervals, merge all overlapping intervals. Each interval is represented as a list of two integers, the start and end. Return the merged intervals sorted by the starting values. Example: Input: intervals = [ [1, 3], [2, 6], [8, 10], [15, 18] ] Output: [ [1, 6], [8, 10], [15, 18] ] Explanation: Intervals [1, 3] and [2, 6] overlap and are merged into [1, 6]. Example Input [(1, 3), (2, 6), (8, 10), (15, 18)]