MergeIntervals

# TC: O(nlogn), SC: O(n)
def mergeOverlappingIntervals(intervals):
    merged = [] # output list
    # Sort the array in ascending order of start values
    sortedIntervals = sorted(intervals, key = lambda x: x[0])
    # Assuming there always will be one interval in the input intervals list
    currInterval = sortedIntervals[0]
    merged.append(currInterval)
    for nextInt in sortedIntervals:
        _, currIntEnd = currInterval
        nextStart, nextEnd = nextInt
        if currIntEnd >= nextStart:
            currInterval[1] = max(currIntEnd, nextEnd)
        else:
            currInterval = nextInt
            merged.append(currInterval)
    return merged