Unacademy Placement Papers 2024

Overview

This page collects Unacademy placement papers from 2024 with previous-year questions, solutions, and the 2024 exam pattern. It is useful when you want real drive history: what the OA looked like, which question types repeated, and how solutions were approached. Work through the papers below to build speed and accuracy, then compare against newer 2025 material so your prep matches both established Unacademy patterns and the latest shifts.

2024 Pattern

The 2024 Unacademy placement process emphasized DSA mastery and video streaming system design. Online assessment included 2-3 DSA problems.

Unacademy Online Assessment 2024 pattern

Section	Questions	Time	Difficulty
Coding Problems	2-3	90 min	Medium-Hard

Unacademy Placement Papers 2024 - actual questions & solutions

This section contains practice questions styled on Unacademy placement papers 2024 (previous-year pattern), with worked solutions. Use them as timed sectional drills - from student reports drives vary by college and role, so treat this as a high-signal practice bank, not an official paper dump.

Question 1: longest common prefix

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Problem Statement: Find the longest common prefix string amongst an array of strings.

Example:

Input: ["flower","flow","flight"]
Output: "fl"

Solution (Java):

public String longestCommonPrefix(String[] strs) {
    if (strs.length == 0) return "";
    String pref = strs[0];
    for (int i = 1; i < strs.length; i++) {
        while (!strs[i].startsWith(pref)) {
            pref = pref.substring(0, pref.length() - 1);
            if (pref.isEmpty()) return "";
        }
    }
    return pref;
}

Time Complexity: O(S)
Space Complexity: O(1)

Question 2: merge two sorted lists

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Problem Statement: Merge two sorted linked lists and return a new sorted list.

Example:

Input: 1→2→4 , 1→3→4
Output: 1→1→2→3→4→4

Solution (Java):

public ListNode mergeTwoLists(ListNode a, ListNode b) {
    ListNode dummy = new ListNode(0), cur = dummy;
    while (a != null && b != null) {
        if (a.val <= b.val) { cur.next = a; a = a.next; }
        else { cur.next = b; b = b.next; }
        cur = cur.next;
    }
    cur.next = (a != null) ? a : b;
    return dummy.next;
}

Time Complexity: O(n + m)
Space Complexity: O(1)

Question 3: two sum

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Problem Statement: Given an array of integers and a target, return indices of two numbers that add up to target.

Example:

Input: nums = [2, 7, 11, 15], target = 9
Output: [0, 1]

Solution (Java):

public int[] twoSum(int[] nums, int target) {
    Map<Integer, Integer> map = new HashMap<>();
    for (int i = 0; i < nums.length; i++) {
        int need = target - nums[i];
        if (map.containsKey(need)) return new int[]{map.get(need), i};
        map.put(nums[i], i);
    }
    return new int[]{};
}

Time Complexity: O(n)
Space Complexity: O(n)

Question 4: detect cycle in linked list

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Problem Statement: Return true if the linked list has a cycle.

Example:

Input: 3→2→0→-4→(back to 2)
Output: true

Solution (Java):

public boolean hasCycle(ListNode head) {
    ListNode slow = head, fast = head;
    while (fast != null && fast.next != null) {
        slow = slow.next;
        fast = fast.next.next;
        if (slow == fast) return true;
    }
    return false;
}

Time Complexity: O(n)
Space Complexity: O(1)

Question 5: binary tree level order

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Problem Statement: Return the level-order traversal of a binary tree.

Example:

Input: [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]

Solution (Java):

public List<List<Integer>> levelOrder(TreeNode root) {
    List<List<Integer>> res = new ArrayList<>();
    if (root == null) return res;
    Queue<TreeNode> q = new ArrayDeque<>();
    q.add(root);
    while (!q.isEmpty()) {
        int sz = q.size();
        List<Integer> level = new ArrayList<>();
        for (int i = 0; i < sz; i++) {
            TreeNode n = q.poll();
            level.add(n.val);
            if (n.left != null) q.add(n.left);
            if (n.right != null) q.add(n.right);
        }
        res.add(level);
    }
    return res;
}

Time Complexity: O(n)
Space Complexity: O(n)

Question 6: reverse a string

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Problem Statement: Given a string, return it reversed.

Example:

Input: "placement"
Output: "tnemecalp"

Solution (Java):

public String reverse(String s) {
    return new StringBuilder(s).reverse().toString();
}

Time Complexity: O(n)
Space Complexity: O(n)

Question 7: check palindrome

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Problem Statement: Return true if the string reads the same forward and backward (ignore case).

Example:

Input: "Level"
Output: true

Solution (Java):

public boolean isPalindrome(String s) {
    s = s.toLowerCase();
    int i = 0, j = s.length() - 1;
    while (i < j) {
        if (s.charAt(i++) != s.charAt(j--)) return false;
    }
    return true;
}

Time Complexity: O(n)
Space Complexity: O(1)

Question 8

Q8: Time complexity of binary search on a sorted array of n elements is?

Solution:

Each step halves the search space → O(log n).

Answer: O(log n)

Question 9

Q9: Worst-case time complexity of quicksort is?

Solution:

Unbalanced partitions (already sorted with bad pivot) → O(n²).

Answer: O(n²)

Question 10

Q10: Which protocol is connection-oriented at the transport layer?

Solution:

TCP is connection-oriented; UDP is connectionless.

Answer: TCP

Question 11

Q11: In OOP, hiding internal details and showing only essential features is called?

Solution:

This is the definition of Encapsulation (often paired with abstraction in interviews).

Answer: Encapsulation

Key insights from 2024 Unacademy Online Assessment

1. Coding Section is Critical: Must solve 2-3 coding problems correctly to advance
2. Video Streaming Focus: Strong emphasis on video streaming systems, playlist management, content delivery
3. Time Management: 2-3 problems in 90 minutes requires excellent speed and accuracy
4. Success Rate: Only 10-15% cleared OA and advanced to interviews
5. Platform: Unacademy assessment platform or HackerRank
6. Focus Areas: Arrays, trees, graphs, dynamic programming, video streaming systems, playlist management

Unacademy 2024 interview experiences

Based on candidate experiences from 2024 Unacademy interviews:

2024 Interview Process:

1. Online Assessment (90 minutes): 2-3 coding problems
2. Technical Phone Screen (45-60 minutes): Coding problems, algorithm discussions, video streaming concepts
3. Onsite Interviews (4-5 rounds, 45-60 minutes each):

• Coding rounds (2-3): Algorithms, data structures, problem-solving
• System Design rounds: Video streaming platforms, playlist management, content delivery, live classes
• Behavioral rounds: Problem-solving approach, education passion, impact

Common 2024 Interview Topics:

• Coding: Arrays, strings, trees, graphs, dynamic programming, playlist algorithms
• System Design: Video streaming platforms, playlist management, content delivery, live classes
• Behavioral: Problem-solving, education passion, teamwork, impact
• Unacademy Technologies: Video streaming platforms, playlist management, content delivery, live classes

2024 Interview Questions Examples:

• Video Playlist Management
• Design Unacademy’s video streaming platform (System Design)
• Design Unacademy’s playlist management system (System Design)
• Video streaming and content delivery algorithms

Success Tips:

• Strong coding performance is essential - solve problems optimally
• Understand video streaming concepts and content delivery systems
• Practice system design for video streaming platforms and playlist management
• Prepare examples demonstrating problem-solving and education passion
• Learn Unacademy’s products and video streaming technologies
• Practice explaining your thought process clearly

For detailed interview experiences, visit Unacademy Interview Experience page.

Preparation tips for Unacademy 2024 pattern

1. Master Coding Fundamentals: Focus on solving 2-3 coding problems correctly - arrays, trees, graphs, DP
2. Video Streaming Knowledge: Strong understanding of video streaming systems, playlist management, content delivery
3. Practice Previous Year Papers: Solve Unacademy OA papers from 2020-2024 to understand patterns
4. Time Management: Practice completing 2-3 coding problems in 90 minutes
5. LeetCode Practice: Solve 200+ LeetCode problems focusing on arrays, strings, trees, graphs (medium-hard difficulty)
6. Video Streaming Focus: Practice problems related to video streaming systems and playlist management
7. System Design Mastery: Learn video streaming platform design, playlist management, content delivery
8. Unacademy Technologies: Learn video streaming platforms, playlist management, content delivery, live classes
9. Behavioral Preparation: Prepare examples using STAR format - problem-solving, education passion, impact
10. Mock Tests: Take timed practice tests to improve speed and accuracy

Related resources

Unacademy 2025 papers→

Latest Unacademy placement papers with current year questions

Unacademy coding questions→

Complete collection of Unacademy coding problems with solutions

Unacademy interview experience→

Real interview experiences from successful candidates

Unacademy preparation guide→

Comprehensive preparation strategy for Unacademy placement

Unacademy main page→

Complete Unacademy placement guide with eligibility, process, and salary

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Practice 2024 papers to understand Unacademy OA pattern and prepare effectively!