Those are codes related to programming contests and they are in UVa Online Judge.
Each folder has a number which is the identifier of the problema on UVa website. Inside of the folder we have two files Main.cpp and test.txt.
To run the problems you just have to
g++ Main.cpp
And
./a.out < test.txt
I am an iOS Developer, besides that most of those codes are written in C++, because I want to learn a new language and learning is always cool!!!! To check my status on UVA.
Happy Coding to all!!! :)