Binary Search on array
Last updated: December 3, 2025
Quick Overview
Given a sorted array of integers, implement a binary search algorithm to determine the index of a target value. If the target is not found, return -1. Your solution should have a time complexity of O(log n).
Optiver
December 3, 202583
10
3,638 solved
Given a sorted array of integers, implement a binary search algorithm to determine the index of a target value. If the target is not found, return -1. Your solution should have a time complexity of O(log n).
This coding problem is frequently asked during Onsite at Optiver. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Optiver expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
- Discuss multiple approaches and trade-offs before coding
- Implement an optimal solution with clean, production-quality code
- Handle all edge cases including boundary conditions and invalid input
- Optimize both time and space complexity with clear justification
- Test your solution systematically with well-chosen examples
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- How would you test this solution thoroughly?
- How would you modify your solution to handle streaming input?
- How would you parallelize this solution?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
The problem requires us to implement a binary search algorithm on a sorted array to find the index of a target value. The binary search algorithm is suitable here because it efficiently narrows down t...
Approach
- Initialize Pointers: Start with two pointers,
leftat the beginning of the array (index 0) andrightat the end (index len(array) - 1). - Loop Until Pointers Meet: While
leftis less...
Submit Your Answer
