Ola

Role: Full Stack Developer

College: Not Specified (Internship at Honeywell and IIT BHU mentioned)

Interview Date: July 2025 (Last Updated)

Interview Type: Off-Campus (Telephonic, Online Test, Face-to-Face, HR)

Result: Selected

Difficulty: Easy-Medium

Rounds: 6 rounds

Topics Asked: OOP, Linked List, Binary Tree, Puzzles, Arrays, Strings, LRU Cache, Projects, Binary Search, K Most Frequent Strings/Words, System Design (Toll booth system, Finding cabs nearby), Behavioral.

Experience:

This candidate applied off-campus for a Full Stack Developer role at OLA and was selected. The interview process involved six rounds.

Round 1: Telephonic (45 minutes)

• "Tell me about yourself."
• Rapid-fire questions from OOP.
• Basic approach to reverse alternate nodes in a linked list without modifying data.
• How many tree traversals are required to identify a unique tree, and which ones?
• Three ants and a triangle puzzle, then derive a generalized formula for an n-sided shape.

Round 2: Online Test (HackerRank - 120 minutes)

• 5 questions mainly on arrays, strings, and LRU cache.

Round 3: Face-to-Face at Ola Campus (approx. 1 hour)

• Discussion about projects done during internships at Honeywell and IIT BHU.
• Simple question to reverse words in a given string and write code.
• Find the first occurrence of 0 in a sorted array of 0s and 1s (candidate gave binary search approach).
• Complicated follow-up: Find the first occurrence of 0 in an infinite sorted array (candidate used binary search with doubling end index).

Round 4: Face-to-Face Technical Interview (approx. 1 hour)

• Given an array of strings, print the K most frequent occurring strings (candidate used k-sized max heap and coded it, handling boundary cases).

Round 5: Managerial Round (approx. 40 minutes)

• Design a toll booth system for Ola cabs, explaining necessary functions and data structures.
• Discussion on internship at GeeksforGeeks and explanation of articles written (specifically a cab allocation article).
• Question: Finding cabs nearby.

Round 6: HR Round (approx. 30 minutes)

• General questions: strengths and weaknesses, "Why do you want to join Ola?", salary expectations.