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Find power-of-two subarrays within sum range

Last updated: Mar 29, 2026

Quick Overview

This question evaluates a candidate's ability to design efficient array-based algorithms, reason about subarray sums, algorithmic complexity, and appropriate data-structure choices within the Coding & Algorithms domain.

  • Medium
  • Meta
  • Coding & Algorithms
  • Software Engineer

Find power-of-two subarrays within sum range

Company: Meta

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: Medium

Interview Round: Technical Screen

Given an integer array nums and an integer k, find all subarrays whose length is a power of two and whose sum lies in the inclusive range [k, 2k]. Return the list of index ranges. Provide an algorithm faster than O(n^ 2). For non-negative nums, use sliding windows across candidate lengths (1, 2, 4, ...). For arrays with negative values, propose a prefix-sum plus balanced tree or hash-bucketing strategy and analyze complexity.

Quick Answer: This question evaluates a candidate's ability to design efficient array-based algorithms, reason about subarray sums, algorithmic complexity, and appropriate data-structure choices within the Coding & Algorithms domain.

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Meta
Aug 7, 2025, 12:00 AM
Software Engineer
Technical Screen
Coding & Algorithms
1
0

Given an integer array nums and an integer k, find all subarrays whose length is a power of two and whose sum lies in the inclusive range [k, 2k]. Return the list of index ranges. Provide an algorithm faster than O(n^ 2). For non-negative nums, use sliding windows across candidate lengths (1, 2, 4, ...). For arrays with negative values, propose a prefix-sum plus balanced tree or hash-bucketing strategy and analyze complexity.

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