https://www.rookieslab.com Blog about software engineering, design, competitive programming and my projects. en-us Ravi Ojha https://www.rookieslab.com/posts/how-to-sweep-a-multi-account-bitcoin-electrum-wallet https://www.rookieslab.com/posts/how-to-sweep-a-multi-account-bitcoin-electrum-wallet Sun, 28 Nov 2021 00:00:00 GMT How to sweep a multi-account Bitcoin Electrum wallet through Trezor if you can't export the mnemonic. https://www.rookieslab.com/posts/dont-be-stuck-at-dev-environment-setup https://www.rookieslab.com/posts/dont-be-stuck-at-dev-environment-setup Wed, 17 Jun 2020 00:00:00 GMT One of the worst feelings as a developer is not able to work on what you set out to do. Instead, you spent the entire day setting up the repository on your local system. And what's worse? It's the first week of your new job. https://www.rookieslab.com/posts/python-caveats-multiline-comment-inside-a-dict https://www.rookieslab.com/posts/python-caveats-multiline-comment-inside-a-dict Wed, 22 May 2019 00:00:00 GMT How to put multiline comments in python dict? Should we use triple quotes style or multiline hashes? https://www.rookieslab.com/posts/t-shaped-smart-creatives https://www.rookieslab.com/posts/t-shaped-smart-creatives Thu, 02 May 2019 00:00:00 GMT What do they bring to the table? https://www.rookieslab.com/posts/ravi-ojha-on-leaving-hackerearth https://www.rookieslab.com/posts/ravi-ojha-on-leaving-hackerearth Tue, 31 Oct 2017 00:00:00 GMT Thank you, HackerEarth. I'll always cherish the memories we've created. Goodbye! https://www.rookieslab.com/posts/how-to-become-better-at-reading-and-debugging-code https://www.rookieslab.com/posts/how-to-become-better-at-reading-and-debugging-code Sun, 07 May 2017 00:00:00 GMT Reading unknown code is usually intimidating, however, our ability to read and debug code matters more than we can write, yet we are never taught anything about it. Let's see how we can improve our ability to read and debug code. https://www.rookieslab.com/posts/is-it-boring-working-in-web-development-startups https://www.rookieslab.com/posts/is-it-boring-working-in-web-development-startups Sat, 15 Apr 2017 00:00:00 GMT Whenever I get in conversation with junior undergrads, they often ask if it is monotonous and boring working on web technologies. I used to think the same way 3-4 years ago, however, after having the first hand experience, I think otherwise. https://www.rookieslab.com/posts/a-millennials-thoughts-on-embarking-as-a-software-engineer https://www.rookieslab.com/posts/a-millennials-thoughts-on-embarking-as-a-software-engineer Sat, 11 Feb 2017 00:00:00 GMT We, the new generation of software engineers, love to talk about creating an impact. We attend overnight hackathons to build the next big thing. Good that we can build an app in 24 hours, but is it really a production ready codebase? Are we carried away with the agility brought in by our generation? https://www.rookieslab.com/posts/extended-euclid-algorithm-to-find-gcd-bezouts-coefficients-python-cpp-code https://www.rookieslab.com/posts/extended-euclid-algorithm-to-find-gcd-bezouts-coefficients-python-cpp-code Sat, 04 Feb 2017 00:00:00 GMT We will see how to use Extended Euclid's Algorithm to find GCD of two numbers. It also gives us Bézout's coefficients (x, y) such that ax + by = gcd(a, b). We will discuss and implement all of the above problems in Python and C++ https://www.rookieslab.com/posts/how-to-find-multiplicative-inverse-of-a-number-modulo-m-in-python-cpp https://www.rookieslab.com/posts/how-to-find-multiplicative-inverse-of-a-number-modulo-m-in-python-cpp Sat, 28 Jan 2017 00:00:00 GMT What is Multiplicative Inverse? What is Modular Multiplicative Inverse? How to find Modular Multiplicative Inverse? How to find Multiplicative Inverse of a number modulo M i.e. under M? How to find Modular Multiplicative Inverse in an efficient way? We will discuss and implement all of the above problems in Python and C++ https://www.rookieslab.com/posts/fastest-way-to-check-if-a-number-is-prime-or-not https://www.rookieslab.com/posts/fastest-way-to-check-if-a-number-is-prime-or-not Sat, 21 Jan 2017 00:00:00 GMT How to check if a given number is a prime number? What is the most efficient way to check if a number is prime or not? How to find prime numbers in a given list of numbers? We will discuss and implement all of the above problems in Python and C++ https://www.rookieslab.com/posts/most-efficient-way-to-find-all-factors-of-a-number-python-cpp https://www.rookieslab.com/posts/most-efficient-way-to-find-all-factors-of-a-number-python-cpp Sat, 14 Jan 2017 00:00:00 GMT First, we will see how to find all factors of a number using brute force. Then we will improve upon that to find all factors of a number using the most efficient method and code it in C++ as well as Python https://www.rookieslab.com/posts/what-it-takes-to-develop-test-and-release-a-software-product https://www.rookieslab.com/posts/what-it-takes-to-develop-test-and-release-a-software-product Sat, 07 Jan 2017 00:00:00 GMT When we talk about developing a software product, we often overlook what goes on in the life of an engineer. The software is not just about code, much like how a journey is not about destination. https://www.rookieslab.com/posts/hobbyist-competitive-programmer-to-software-engineer-at-hackerearth https://www.rookieslab.com/posts/hobbyist-competitive-programmer-to-software-engineer-at-hackerearth Wed, 09 Sep 2015 00:00:00 GMT During four years of Computer Engineering, I used to think about what I should pursue as professional career. Loved designing graphic posters, thoroughly enjoyed Competitive Programmer and it was immensely satisfying to build software products to solve real world problems. So much dilemma and I ended up being a Software Engineer at HackerEarth https://www.rookieslab.com/posts/ravi-ojha-computer-science-svnit-surat-life-post https://www.rookieslab.com/posts/ravi-ojha-computer-science-svnit-surat-life-post Sun, 16 Aug 2015 00:00:00 GMT Life is like a real-time strategy game. Its great to know beforehand how others played it when they were at your situation. In this short post, I'm summing up scenarios I faced, decisions I made and their outcomes during four years of Computer Engineering. https://www.rookieslab.com/posts/build-make-GIMP-from-source https://www.rookieslab.com/posts/build-make-GIMP-from-source Fri, 29 Aug 2014 00:00:00 GMT GNU Image Manipulation Program is one of the best open source projects out there as an alternative for PhotoShop. This post discusses how we can build and install GIMP from source code. I did it because I wanted to contribute to the project. https://www.rookieslab.com/posts/what-is-memoization-what-is-dynamic-programming https://www.rookieslab.com/posts/what-is-memoization-what-is-dynamic-programming Sun, 07 Jul 2013 00:00:00 GMT Memoization or Dynamic Programming is a technique of remembering solutions to sub-problems which will help us solve a larger problem. https://www.rookieslab.com/posts/cpp-python-code-to-find-gcd-of-a-list-of-numbers https://www.rookieslab.com/posts/cpp-python-code-to-find-gcd-of-a-list-of-numbers Sun, 02 Jun 2013 00:00:00 GMT First, we will see how to find GCD of two numbers. It is also known as Highest Common Factor - HCF. Then we will move on to find the GCD of a list of numbers and code it in both C++ as well as Python https://www.rookieslab.com/posts/fast-power-algorithm-exponentiation-by-squaring-cpp-python-implementation https://www.rookieslab.com/posts/fast-power-algorithm-exponentiation-by-squaring-cpp-python-implementation Sat, 18 May 2013 00:00:00 GMT We know how to find 2 raised to the power 10. But what if we have to find 2 raised to the power very large number such as 1000000000? We discuss how to find solution to such a problem using an fast, efficient algorithm https://www.rookieslab.com/posts/collection-of-python-blogs-for-beginners-mitx-600x-edx https://www.rookieslab.com/posts/collection-of-python-blogs-for-beginners-mitx-600x-edx Sat, 12 Jan 2013 00:00:00 GMT I took MITx 6.00x on edX in 2012 and we were taught basics of Python along-with programming in general. While revisiting the videos in the end, I thought of creating a quick guide for myself and everyone else. https://www.rookieslab.com/posts/how-to-compute-time-complexity-order-of-growth-of-any-program https://www.rookieslab.com/posts/how-to-compute-time-complexity-order-of-growth-of-any-program Fri, 11 Jan 2013 00:00:00 GMT Time Complexity gives us an idea of running time of any program w.r.t. the size of input fed to the program. Order of Growth is just another word for Time Complexity. https://www.rookieslab.com/posts/python-dictionary-and-its-properties https://www.rookieslab.com/posts/python-dictionary-and-its-properties Thu, 10 Jan 2013 00:00:00 GMT Dictionary is a generalization of a List. Dictionary stores (key, value) pair for easier value access in future using the key. We see how it is different from a list and its properties. https://www.rookieslab.com/posts/python-lists-and-list-methods https://www.rookieslab.com/posts/python-lists-and-list-methods Wed, 09 Jan 2013 00:00:00 GMT Declaring, Accessing, Slicing, Deleting and Updating Lists and its elements in Python https://www.rookieslab.com/posts/python-tuples-and-basic-operations-on-tuples https://www.rookieslab.com/posts/python-tuples-and-basic-operations-on-tuples Wed, 09 Jan 2013 00:00:00 GMT What is a tuple? How is it different from a list? And some basic methods on Tuples https://www.rookieslab.com/posts/basics-of-recursion-in-programming-using-a-simple-example https://www.rookieslab.com/posts/basics-of-recursion-in-programming-using-a-simple-example Tue, 08 Jan 2013 00:00:00 GMT Recursion is a technique of finding solutions to larger problems using known solution of smaller problems. For me atleast, it was hard to get the understanding of recursion. In this post we see an iterative and recursive version of one problem in programming. https://www.rookieslab.com/posts/linear-search-vs-bisection-search-in-python https://www.rookieslab.com/posts/linear-search-vs-bisection-search-in-python Tue, 08 Jan 2013 00:00:00 GMT When it comes to searching an element within a list of elements, our first approach is searching sequentially through the list. Let's take a look at a better method, Binary Search https://www.rookieslab.com/posts/finding-square-root-using-guess-and-check-algorithm-in-python https://www.rookieslab.com/posts/finding-square-root-using-guess-and-check-algorithm-in-python Mon, 07 Jan 2013 00:00:00 GMT Guess and Check is one of the most common methods of finding solution to any problem. We will see how it can be used to find a close approximation of square root of any number https://www.rookieslab.com/posts/iteration-or-loop-in-python https://www.rookieslab.com/posts/iteration-or-loop-in-python Sun, 06 Jan 2013 00:00:00 GMT For and While loop constructs in Python enable us to perform repetitive tasks or help us iterate over a string or a list or any iterable object https://www.rookieslab.com/posts/branching-with-if-else-elif-in-python https://www.rookieslab.com/posts/branching-with-if-else-elif-in-python Sat, 05 Jan 2013 00:00:00 GMT If this Then that! Python provides us with if, else and elif to add conditions in code and branch it like a tree https://www.rookieslab.com/posts/python-strings-and-frequently-used-str-methods https://www.rookieslab.com/posts/python-strings-and-frequently-used-str-methods Fri, 04 Jan 2013 00:00:00 GMT Accessing string characters via index, string slicing and frequently used str methods such as find, replace. How to read input from Standard Input STDIN https://www.rookieslab.com/posts/arithmetic-and-logical-operators-in-python https://www.rookieslab.com/posts/arithmetic-and-logical-operators-in-python Thu, 03 Jan 2013 00:00:00 GMT How to perform arithmetic and logical operations on Python variables of different types https://www.rookieslab.com/posts/python-objects-and-types https://www.rookieslab.com/posts/python-objects-and-types Wed, 02 Jan 2013 00:00:00 GMT Everything in Python is an object! Every object in Python has a type. This post discusses some of them with examples https://www.rookieslab.com/posts/python-syntax-static-semantics-semantics-of-a-language https://www.rookieslab.com/posts/python-syntax-static-semantics-semantics-of-a-language Sat, 29 Dec 2012 00:00:00 GMT Before we begin with any language, it's important to know the aspects of the language. What is Syntax? Semantics? Static Semantics? This post explain these terms with examples. https://www.rookieslab.com/posts/playing-with-at-photoshop-and-gimp https://www.rookieslab.com/posts/playing-with-at-photoshop-and-gimp Wed, 26 Dec 2012 00:00:00 GMT As a kid, I admired designs and wanted to pursue design as a career. (Un)fortunately, I married Software Engineering. These were some of the designs that were created for college fests.