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Solution: Interval List Intersections

Explore how to compute intersections between two sorted lists of intervals by iterating through them with two pointers. Learn to compare interval endpoints, add overlapping intervals to the result, and efficiently move through the lists. Understand the optimized approach that runs in linear time and uses constant space, helping you solve this common coding interview problem confidently.

Statement

Given two lists of closed intervalsA closed interval [start, end] (with start <= end) includes all real numbers x such that start <= x <= end., intervalListA and intervalListB, 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:

  • intervalListA[i] = [starti, endi]

  • intervalListB[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:

  • 00 \leq ...