Coding questions
Unacademy Online Assessment
Overview
Detailed public write-ups on the Unacademy online test are still hard to find.
What public reports and campus notices usually say (still verify officially):
| Item | Working note |
|---|---|
| Online test name | Unacademy Online Assessment |
| Focus areas (metadata) | DSA, aptitude |
| Languages (metadata) | Python, Java, JavaScript. |
| Reported round names | OA (90 min, 2-3 coding) → Technical 1 (DSA) → Technical 2 (system design/video streaming) → Managerial → HR. |
Practice drills
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
Unacademy 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
Unacademy 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
Unacademy 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
Unacademy 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.
What to do next
- Open the official careers page or your college placement email for Unacademy
- Search GeeksforGeeks + Reddit for
Unacademy interview experience - Use Faceprep / PrepInsta only if they match your placement email