dsa

Hello Coders

This is a DSA repository.

NOTE:

1. If this PR is for Hacktoberfest please mention it in description, to ensure label is not missed.
2. Kindly add your files in right language directory and if directory is not present please create accordingly. Eg. Java files should be added inside Java directory.
3. If point 2 is not point, your PR might not get merged.