top 3 best coding practicing open sources.

 HACKERRANK:  Technology firm HackerRank specialises in programming competitions for both                                            consumers and companies. Competitors write programmes to the stated specifications in order to win. The programming challenges on HackerRank cover a wide range of computer scientific disciplines and can be completed in a number of programming languages, including Java, C++, PHP, Python, SQL, and JavaScript.

The majority of programming challenges on HackerRank are divided into several key computer science fields, such as database administration, mathematics, and artificial intelligence, among other topics.

When a programmer submits a response to a programming challenge, the output's accuracy is assessed.In order to encourage user competitiveness, programmers are then ranked globally on the HackerRank scoreboard and awarded badges for their accomplishments. Along with hosting individual coding challenges, HackerRank also organises competitions (commonly referred to as "CodeSprints") in which participants compete on the same programming problems over the course of a specified amount of time and are ranked at the end of the event. The expanding gamification trend in competitive computer programming is represented by HackerRank. Coders can utilise the consumer-facing portion of their website for free.

Codeforces:   On the website Codeforces, programming competitions are held. It is looked after                         by a team of talented programmers from ITMO University under the direction of Mikhail Mirzayanov. Since 2013, Codeforces asserts to have more participants actively competing than Topcoder. More than 600,000 users have enrolled as of 2018. Top sport programmers like Gennady Korotkevich, Petr Mitrichev, Benjamin Qi, and Makoto Soejima, as well as other programmers interested in advancing their careers, use websites like Codeforces and others that are similar to them.

The following capabilities are available on the Codeforces platform, which is frequently used for practising for programming competitions:

• About once a week, brief (2-hour) competitions dubbed "Codeforces Rounds" are organised.
• 1-2 times every month, educational competitions (2–2.5 hours, with a 12-hour (24-hour) hacking session);
• Challenge/hack the responses of other competitors;
• Use the "Polygon" function to create and test puzzles, and solve issues from prior competitions for training purposes.
• Interpersonal communication with internal public blogging

A team of competitive programmers from Saratov State University, led by Mike Mirzayanov, founded Codeforces. It was initially developed for those who enjoyed completing chores and competing. [2] With 175 participants, the first Codeforces Round took place on February 19, 2010. Over 800 rounds had been held as of the end of August 2022, with an average of over 9000 registered competitors every round. In order to reflect that the technology was still being developed, Codeforces Rounds were previously referred to as "Codeforces Beta Rounds" before 2012.

LeetCode:  The website Leetcode is truly fantastic for helping you get ready for an FAANG                       interview. To reap the greatest benefits, I heartily advise you to purchase the premium version. Some extra questions that are frequently asked during an FAANG interview are unlocked by the premium edition. Additionally, you can choose particularly from inquiries that came from a certain company.

Without a doubt, Leetcode is an excellent tool for getting ready for technical interviews. Studying the plethora of highly interesting and practical coding questions might help you better prepare for an interview.

In fact, the majority of the questions are extremely comparable to those that are given in interviews, thus practising with Leetcode will help you have a clear understanding and be prepared.

However, this does not imply that you must complete them all or that you will find employment once you have.

It's impossible for some people to memorise responses without completely comprehending them because it's uncommon for the same question to be asked in an interview.

Additionally, a lot of individuals believed that technical interviews just dealt with code, whereas in fact they were exams. Along with your code, a number of other factors are assessed, including communication and analytical abilities. Don't forget to include system design interviews as well. Therefore, when preparing, it is best to integrate several sets of resources, books, and websites and pay attention to your communication.