Shyamkant Limaye - Python Quick Interview Guide

Smita, my charming wife,
without whose silent support this project would never
have been possible.

Professor Shyamkant Limaye spent 18 years in the computer industry and 30 years in teaching the students of Electronics Engineering. His experience includes a 2-year stint as a System Analyst in the USA. In 1971, he graduated from the Visvesvaraya National Institue of Technology in Electrical engineering with a gold medal. He did his Masters from IIT Kanpur, and is a Doctorate in Electronics from RTM Nagpur University. He has guided 10 students for PhD. He has published a textbook on VHDL programming in 2007. He has also published a thriller novel entitled Dual reality in 2011. He retired as a Professor in Electronics and Telecomm Dept. at St. Vincent Pallotti College of Engineering and Technology, Nagpur.

Dr. Manoj B. Chandak is head of Computer Science and Engineering at Ramdeobaba College of Engineering and Management, Nagpur. He holds a Ph.D. in Computer Science and Engineering from Nagpur University. He also holds M.E. in Computer science where he was a topper and B.E. in Computer Technology from Nagpur university where he stood second. He is an acknowledged academician with over 22 years of teaching experience with more than 60 research publications in referred journals and conferences. A recognized supervisor in doctoral research in RTM Nagpur University and SGB Amravati University, his research interests are in NLP, Big Data, Information Retrieval, and Mobile & Wireless Technology. He conducts courses in Design and Analysis of Algorithms, Language Processing [Compiler Design], Advances in Algorithms, and Natural Language Processing.

There are a few people I want to thank for helping me to bring this book into existence.

First is Mr. Rohan Vaidya, my young colleague at St. Vincent Pallotti College of Engineering and Technology. He urged me to learn Python because he said that tomorrows engineers and scientists are going to need it, and as a teacher, it was my duty to teach them. I have been a diehard fan of C++ for the most of my life. But due to Rohans persuasion, I decided to learn Python. Interestingly, it was my B.E. final year student, Pravesh Bawangade, who gave me the first lesson of Python. I found the language to be really useful.

After interacting with students going for campus interviews, I realized that there are many introductory books on Python and many advanced level books dealing with the data science and artificial intelligence. But, there is no book that grills them into coding and teaches algorithms and data structures from a competition point of view. I, therefore, decided to write this book.

I am thankful to my colleagues Dr. Ms. Hema Kale, Dr. Manoj Chandak, and Dr. Rajesh Pande, for going through my early drafts and giving valuable suggestions.

Finally, I must thank BPB Publications for accepting my idea and giving continuous support during the editing process.

It gives me great pleasure to offer this book to the students. C++ was invented in 1979 and Python was invented 10 years later, in 1989. C++, and its cousin Java, ruled the programming world for many years. However, they are loosening their grip now. Python offers more flexible language constructs and platform independence. But the recent upsurge in the demand for Python is triggered by a rich set of libraries in the public domain, especially in the area of artificial intelligence (AI).

Many excellent books have been written on the Python programming. Some are basic and some teach advanced topics, like, machine learning and deep learning. But to get into a good company, firstly, a student has to clear an aptitude test and a coding test. While many books exist on the aptitude preparation, there is a dearth of books to prepare the students for a coding interview. The standard university curriculum does not provide this knowledge. The coding test can be given in many languages like C, C++, or Java. However, since Python is the language of the future, it is better to give it in Python.

There are some resources available on the internet, but they are scattered over many places, and they neither provide proper explanation, nor provide a graded path from easy to hard problems. Moreover, one cannot become a coding wizard merely by copy-pasting somebodys code without understanding. That is precisely why this book has been written. In addition, a college may choose this book as a reference book for the lab courses in Python.

It is not possible to cover all the possible problems in a small book. But it is neither necessary, nor desirable. The 75 problems presented in this book will guide the students to the path of self-reliance and confidence.

Every year, the placement agencies and IT companies conduct coding tests for the graduating batch. Many of them use an artificial intelligence-based evaluation tool that senses the logic of the students. If you get the answer right, it is good. But, even if you dont get a valid answer, or cannot remove the compilation errors, or cannot remove the run time errors, the tool is able to sense your logic. It is also able to sense the time complexity and the space complexity of the code. Most companies in India, and abroad, use similar sets of questions and similar evaluation tools. In general,