Optimize partitioning for without recursion
Last updated: March 23, 2026
Quick Overview
Given an array of integers, implement a function to partition the array into two segments such that all elements less than a specified pivot value are on one side and all elements greater than or equal to the pivot are on the other side, without using recursion. The function should modify the array in place and return the indices of the two segments.
PayPal
March 23, 202668
4
2,041 solved
Given an array of integers, implement a function to partition the array into two segments such that all elements less than a specified pivot value are on one side and all elements greater than or equal to the pivot are on the other side, without using recursion. The function should modify the array in place and return the indices of the two segments.
This coding problem is frequently asked during Take-home Project at PayPal. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. PayPal expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
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
- Can you solve this iteratively instead of recursively (or vice versa)?
- How would your solution change if the input was sorted?
- Can you solve this in a single pass?
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 partition an array based on a pivot value, placing all elements less than the pivot on one side and all elements greater than or equal to the pivot on the other side. This c...
Approach
- Initialize two pointers: Start one pointer (
left) at the beginning of the array and the other pointer (right) at the end. - Iterate while
leftis less thanright:- Increment th...
Submit Your Answer
