Add Hackerrank solutions for Interview Preparation Kit in C++

[danhenriquesc]

https://www.hackerrank.com/interview/interview-preparation-kit

[surya-prakash-susarla]

I've solved a couple of them can I add them here ?

[danhenriquesc]

Yes, just open a PR.
Don't forget to update the README.md with the solutions and update CONTRIBUTORS.md with your nickname

[surya-prakash-susarla]

Hey thanks for the reply, I just completed the changes but haven't changed the readme since there was no section for the interview preparation kit. I shall update the contributors.md file.

[surya-prakash-susarla]

@danhenriquesc I've just modified the readme to contain the details of all the solutions newly added to the interview preparation kit folders. Have a look :-)