What should I focus on learning for my C++ competition this week?

Question

Ive signed up for a C++ competition and I don't know what to focus on. I'm trying to not learn what I wont really need. I'm aware this is a difficult question as an example file manipulation is important thing I need to get better at.

Answer 1

https://www.geeksforgeeks.org/c-tricks-competitive-programming-c-11/

Answer 2

Practice here : www.codechef.com