Solution: Interval List Intersections

Explore how to efficiently find intersections between two sorted lists of closed intervals by using a two-pointer approach. Understand the step-by-step method to compare intervals, identify overlaps, and move pointers accordingly. This lesson helps you implement an optimized solution with O(n + m) time complexity, improving over the naive nested loop approach.

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Statement
Solution
- Naive approach
- Optimized approach using intervals

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] = [start_i, end_i]
intervalListb[j] = [start_j, end_j]

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

An empty set, if they do not overlap, or
A closed interval [max(start_i, start_j), min(end_i, end_j)] if they do overlap.

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

Constraints:

$0 \leq$ ...