Competitive Programming is a mindsport where participants try to program solutions to various mathematical and algorithmic problems while adhering to run-time and system memory constraints.
This repostiory contains my solutions to thousands of programming challenges from multiple online judges. The purpose of this repo is to serve as a backup of all my solutions, and at the same time serve as a resource for fellow competitive programmers who are searching the internet for clues or solutions to problems that they are stuck on.
I should mention that none of these solutions are written with respect to best Software Engineering practices. The programs are written the way they are so that solutions to problems in competitions can be submitted as fast as possible. In few cases the solutions have small comments describing what the code is doing.
This repostiory also features some good implementations for advanced data structures and algorithms.
Codeforces is one of the most active competitive programming communities on the internet. It is maintained by a group of competitive programmers from ITMO University led by Mikhail Mirzayanov.
Each sub-directory in the Codeforces directory is named after a Codeforces round. The solution for each problem in the round is named after the problem's title with problem index (usually a single alphabet letter).
Based in Japan, AtCoder offers online programming contests on a weekly basis. The contests are offered in Japanese and English. As of 2022, it is one of the most popular platforms of in the Competitive Programming community.
Each sub-directory in the Atcoder directory is named after the Atcoder Contests. The solutions of problems are names as their titles with the problem index.
CodeChef is an online educational program and competitive programming community of global programmers. Code-Chef started as an educational initiative in 2009 by Directi, an Indian software company.
It hosts three featured contests every month (Long Challenge, CookOff, LunchTime & Starters) and gives away prizes and goodies to the winners as encouragement. Apart from these, the platform is also open to the entire programming community, especially academic institutes, and student bodies, to host their own contests.
SPOJ (Sphere Online Judge) is an online judge system with over 315,000 registered users and over 20,000 problems. Tasks are prepared by its community of problem setters or are taken from previous programming contests. SPOJ allows advanced users to organize contests under their own rules and also includes a forum where programmers can discuss how to solve a particular problem.
Apart from the English language, SPOJ also offers its content in Polish, Portuguese and Vietnamese languages. The solution to problems can be submitted in over 40 programming languages, including esoteric ones, via the Sphere Engine. It is run by the Polish company Sphere Research Labs and is one of the oldest online Judge.
Solutions of the problems are names as the title with the problem code prefixed.
CSES Problemset is one of the finest collection of algorithmic programming problems. The goal of the project is to create a comprehensive high quality problem set for learning algorithmic programming.
This directory contains sub-directory of solutions categorised as per the categories of problems on the CSES problemset.
Google also conduct flagship programming competitions as CodeJam, KickStart and HashCode. These coding competitions are conducted every year to assess the coders all around the world. It is a great way to showcase your programming skills and problem-solving skills at the international level.
Meta Hacker Cup (previously known as Facebook Hacker Cup) is an annual international programming competition hosted and administered by Meta. The competition began in 2011 as a means to identify top engineering talent for potential employment at Facebook. The competition consists of a set of algorithmic problems which must be solved in a fixed amount of time. Competitors may use any programming language and development environment to write their solutions.
HackerEarth is an Indian software company headquartered in San Francisco, US, that provides enterprise software that assists organizations with technical hiring. HackerEarth is used by organizations for technical skill assessments and remote video interviewing. In addition, HackerEarth also has built a community of over 4 million developers. In the community, HackerEarth has conducted over 1,000 hackathons and 10,000 programming challenges to date. It also conducts monthly coding challenges like Circuits, Easy.
This directory contains sub-directories of solutions of few of those coding marathons in which I had parcipated.
This directory contains template implementations of some advanced Data Structures and Algorithms that are useful for programming competitions.
Kattis is a programming platform with automatic judging system. Problems on Kattis cover many algorithms and data structures, and they are good practice to pay attention to details, separate the wheat from the chaff in a problem description, and think of edge cases where the algorithm may fail.
Kattis also provide a good archive of many regional progamming contests and ICPC held in the past.
LeetCode is one of the most well-known online judge platforms that you can use to practice your programming skills by solving coding questions. As of 2022, It has 2000+ different problems and an active community that is always there to help you with the solutions you come up with. If your intention is to hone your coding skills, then this online judge platform is one of the best that you can use.
Notice : Few directories may have multiple solutions for the same problem, represented by an extra file, named as just the index of the problem only (single uppercase letter).