Given two lists of closed intervalsA closed interval [start, end] (with start <= end) includes all real numbers x such that start <= x <= end., interval_list_a and interval_list_b, return the intersection of the two interval lists.

Each interval in the lists has its own start and end time and is represented as [start, end]. Specifically:

• interval_list_a[i] = [starti, endi]

• interval_list_b[j] = [startj, endj]

The intersection of two closed intervals i and j is either:

• An empty set, if they do not overlap, or

• A closed interval [max(starti, startj), min(endi, endj)] if they do overlap.

Also, each list of intervals is pairwise disjoint and in sorted order.

Constraints:

• $0 \leq$ interval_list_a.length, interval_list_b.length $\leq 1000$

• interval_list_a.length $+$ interval_list_b.length $>=1$

• $0 \leq$ starti $<$ endi $\leq 10^9$

• endi $<$ starti + 1

• $0 \leq$ startj $<$ endj $\leq 10^9$

• endj $<$ start[j + 1]