I'd like to share my reusable c++ libs I've been using for codeforce contests.

https://github.com/duc0/ContestNeko

Some existing utilities:

• Binary search
• Lowest common ancestor
• Binary Indexed Tree
• Segment Tree
• Heavy light decomposition
• Convex hull
• Prime generator
• Simple matrix algebra
• ...

You are free to use it in contests (subject to codeforces's policy I guess) and any contributions are more than welcome!