HashedIn by Deloitte Software Engineer Interview Questions and Answers

Implementing a stack using two queues to maintain LIFO behavior with FIFO operations.

• Push Operation: Enqueue to empty queue, move elements from non-empty queue, swap queues.

• Pop Operation: Dequeue from the non-empty queue.

• Top Operation: Return the front element of the non-empty queue.

• IsEmpty Operation: Check if the non-empty queue is empty.

• Example: Pushing 1, then 2 results in top being 2; popping gives top as 1.

A complete C++ implementation of a Tic-Tac-Toe game using object-oriented programming principles.

• Use a class 'TicTacToe' to encapsulate game logic and state.

• Implement methods for player moves, checking win conditions, and displaying the board.

• Utilize a 2D array to represent the game board.

• Include error handling for invalid moves.

• Provide a simple text-based interface for user interaction.

Rotate an array of strings to the left by k places efficiently.

• Use the modulo operator to handle cases where k is larger than the array length.

• Example: For array ['a', 'b', 'c', 'd'] and k=2, result is ['c', 'd', 'a', 'b'].

• Reverse the entire array, then reverse the first n-k elements and the last k elements.

• Time complexity is O(n) and space complexity is O(1) if done in place.

Design a database schema for an online cab booking service to manage users, drivers, rides, and payments.

• Users table: Stores user information (e.g., user_id, name, email, phone).

• Drivers table: Contains driver details (e.g., driver_id, name, vehicle_info, license_number).

• Rides table: Records ride details (e.g., ride_id, user_id, driver_id, start_location, end_location, fare, status).

• Payments table: Manages payment ...read more

Design a scalable system using NoSQL and caching for efficient data retrieval and storage.

• Choose a NoSQL database like MongoDB or Cassandra for flexible schema and horizontal scalability.

• Implement caching using Redis or Memcached to reduce database load and improve response times.

• Use a microservices architecture to allow independent scaling of different components.

• Incorporate load balancers to distribute traffic e...read more

Sharding is a database partitioning technique to improve performance and scalability.

• It involves dividing a large database into smaller, more manageable parts called shards.

• Each shard contains a subset of the data and can be stored on a separate server.

• Sharding can be implemented using different strategies such as range-based, hash-based, or round-robin.

• It requires careful planning and coordination to ensure data ...read more

Q1 - Pre order traversal without recursion. Q2 - Reverse a linked list.

• Q1: Use a stack to keep track of nodes. Start with root, push it to stack. Pop top node, print it, push right and left children to stack.

• Q2: Traverse the linked list and change the direction of the pointers. Set the head of the reversed list as the last node of the original list.