You are given two lists of closed intervals,
firstList[i] = [starti, endi] and
secondList[j] = [startj, endj]. Each list of intervals is pairwise disjoint and in sorted order.
Return the intersection of these two interval lists.
A closed interval
[a, b] (with
a < b) denotes the set of real numbers
a <= x <= b.
The intersection of two closed intervals is a set of real numbers that are either empty or represented as a closed interval. For example, the intersection of
[1, 3] and
[2, 4] is