In competitive programming contests, one must write computer programs capable of solving clear-cut problems under the given contraints and limits. Most competitive programmers use C++, Java, or Python.
Start by learning C++ by finding a tutorial such as this. If you have learned some other language such as Java or Python, I recommend you switch to C++. Once you are familiar with the basics, start doing some problems or contests from Codeforces or Atcoder.
Work through some book such as the Competitive Programmer's Handbook to gain some understanding on common algorithms and techniques used in competitive programming.
If you want to add something useful or correct an error, please email me at [email protected] or submit a Pull Request. It would be highly appreciated!
Inspired by https://github.com/bqi343/USACO