Katkat
Back

Implement basic pagination for a list

CoinbaseSoftware Engineer · Technical Screen
MediumSoftware EngineerTechnical ScreenCoding & Algorithms

Last updated

This question evaluates a candidate's competence in array indexing, boundary-condition handling, and simple pagination logic, focusing on correct subarray extraction and off-by-one considerations within given size constraints.

You are given:

  • A zero-indexed array of items items (you can assume it fits in memory).
  • An integer pageSize > 0.

Design and implement a pagination helper that supports the following operations:

  1. Initialize the paginator with the array and pageSize.
  2. Given a page number pageIndex (0-based), return the subarray of items that belongs to that page.
  • Page 0 contains items with indices [0, pageSize - 1] (if they exist),
  • Page 1 contains [pageSize, 2 * pageSize - 1], and so on.
  1. If pageIndex is out of range (no items on that page), return an empty list.

Assume:

  • 0 <= pageIndex
  • 1 <= pageSize <= 10^5
  • 0 <= len(items) <= 10^6

Define the interface and implement the core method(s) for pagination. Focus on clean indexing and handling boundary cases correctly.