Senior Software Engineer L2 Interview Questions and Answers

This code identifies duplicate strings in a text and returns their indices.

• Use a dictionary to store strings and their indices.

• Iterate through the list of strings, updating the dictionary.

• If a string is already in the dictionary, append the current index to its list.

• Example: For input ['apple', 'banana', 'apple'], output is {'apple': [0, 2]}.

SQL is a relational database management system that uses structured query language, while NoSQL is a non-relational database system that does not use SQL.

• SQL databases are table-based and have a predefined schema, while NoSQL databases are document-based, key-value pairs, graph databases, or wide-column stores.

• SQL databases are vertically scalable, while NoSQL databases are horizontally scalable.

• SQL databases are good for complex queries and transactions, while NoSQL database...read more

A class is a blueprint for creating objects in object-oriented programming. An object is an instance of a class.

• A class defines the properties and behaviors of objects.

• An object is a specific instance of a class.

• Classes can be used to create multiple objects with similar characteristics.

• Objects can interact with each other by calling methods defined in their class.

• Example: Class 'Car' can have properties like 'color' and 'model', while an object of class 'Car' can be 'Toyota ...read more

Singleton Design Pattern ensures a class has only one instance and provides a global point of access to it.

• Ensures a class has only one instance by providing a global access point to it

• Commonly used in scenarios where only one instance of a class is needed, such as database connections or configuration settings

• Implemented by making the constructor private and providing a static method to access the single instance

Objects in programming are created by defining a class and instantiating it to create instances of that class.

• Define a class with attributes and methods

• Instantiate the class to create an object

• Access and manipulate object properties and methods

Columnar databases store data in columns rather than rows, allowing for faster query performance and better compression.

• Data is stored in columns rather than rows

• Better suited for analytical queries

• Allows for better compression and faster query performance

• Examples include Amazon Redshift, Google BigQuery

Pub-Sub model is a messaging pattern where senders (publishers) of messages do not program the messages to be sent directly to specific receivers (subscribers).

• Publishers send messages to a central topic or channel

• Subscribers subscribe to the topic or channel to receive messages

• Decouples senders and receivers, allowing for scalability and flexibility