Coding questions
Dell Online Assessment
Overview
Here is how public prep guides and student write-ups describe the Dell online assessment. This is not an official company brochure.
Limited detailed public fresher OA write-ups; pattern notes synthesised carefully from listed sources only.
Usual selection rounds
Rounds students usually mention: Online assessment → Technical interview(s) → HR
| Item | From student reports |
|---|---|
| Platform | Varies by drive |
| Online test summary | Campus patterns vary by software vs hardware/support tracks. Public India fresher write-ups exist across years but section counts shift - use college placement email. |
| Eligibility notes | Drive-specific - confirm notification |
| Branches (reported) | Confirm notification |
Online test sections
Section-level detail not verified in our source set yet - use the placement email / official PDF.
Extra notes from sources
- Public fresher sectional counts are sparse; check your college placement email or official notification for exact section counts.
Sample practice question styles
These are practice questions for speed - not claimed to be from a real Dell live paper.
Coding Q1: Reverse a string in place
Problem: Given a mutable character array representing a string, reverse it in place without allocating another array of the same size.
Approach: Use two pointers at the start and end. Swap characters, then move inward until the pointers meet. Watch empty and single-character inputs.
Complexity: O(n) time, O(1) extra space
Dell tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q2: Check prime
Problem: Write a function that returns true if n is prime and false otherwise. Handle n < 2 correctly.
Approach: Return false for n < 2. Trial-divide from 2 to floor(sqrt(n)). If any divisor divides n evenly, it is composite; otherwise prime.
Complexity: O(√n) time
Dell tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q3: Valid parentheses
Problem: Given a string containing only ‘()[]’, decide whether the brackets are balanced and correctly nested.
Approach: Scan left to right with a stack. Push opening brackets. On a closing bracket, the stack top must be the matching opener. At the end the stack must be empty.
Complexity: O(n) time, O(n) space
Dell tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q4: Two Sum
Problem: Given an array of integers and a target, return indices of two numbers that add up to the target. Assume exactly one solution and you may not use the same element twice.
Approach: Walk the array once. For each value x, check whether target − x was seen earlier in a hash map of value → index. If yes, return both indices; else store x.
Complexity: O(n) time, O(n) space
Dell tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Prep tips from those student reports
- Confirm software vs hardware track
- CS fundamentals
Sources
- Dell Technologies careers (other)
These notes come from public reports and can differ by campus, year, and role. If your college placement email or the official careers/notification PDF says something different, follow that.