Just completed the IBM Online Assessment for the Application Developer – Experience Front End role.
Sharing the coding questions for anyone preparing.

Platform: HackerRank
Questions: 2 Coding
Difficulty: Easy–Medium
Focus Areas: Sliding Window, Hashing, Subarrays / Substrings

🔹 Question 1: Count Subarrays With Product = K

Problem (High-level):
Given an integer array nums and an integer k, return the total number of contiguous subarrays whose product of elements equals k.

• Subarrays may overlap
• Order matters (contiguous only)

Example

nums = [2, 3, 2, 2]
k = 4

Output: 1
Explanation:
Only subarray [2, 2] has product = 4

Key Observations

• Brute-force O(n²) works for small input but may TLE
• Since numbers are positive, sliding window / prefix-product logic helps
• Need to be careful with product overflow and resets

What This Tests

• Subarray enumeration logic
• Edge cases with multiplication
• Optimization thinking

🔹 Question 2: Count Substrings With All Unique Characters

Problem (High-level):
Given a string text, count the number of substrings that contain only distinct characters.

Two substrings are different if they start or end at different positions.

Example

text = "abac"
Output: 8

Valid substrings:
"a", "b", "a", "c", "ab", "ba", "ac", "bac"

Constraints

• 1 ≤ |text| ≤ 10^5
• Only lowercase English letters

Key Observations

• Classic sliding window + frequency map problem
• Maintain a window with no repeating characters
• For each right pointer, count valid substrings ending at that index

What This Tests

• Sliding window mastery
• Hashing / frequency tracking
• Efficient counting logic

🧠 Overall Experience

• Questions were straightforward but required clean logic

• Emphasis was on:

  • Writing efficient solutions
  • Handling edge cases
  • Understanding problem constraints

• Very doable with solid DSA fundamentals

📌 Preparation Tips for IBM OA

• Practice:

  • Sliding window problems
  • Subarray vs substring differences
  • Frequency map techniques

• Focus on clean code + correctness

• Don’t overthink — problems are mostly pattern-based

✅ Final Thoughts

IBM OA felt fair and practical, especially for a Front End–aligned role with strong algorithmic basics.

If anyone else appeared recently and got different questions, feel free to comment and share 👇
All the best to everyone preparing! 🚀