Does someone know any apps about competitive programming?

Answer 1

HackerEarth, Codewars, codechef.
if you're a beginner, I suggest you start with HackerRank. These are websites btw.

Answer 2

Have started with HackerEarth. Found it a little difficult. Is HackerRank a bit easier @Jobelle?

Answer 3

what you mean by competitive?

Answer 4

uHunt, Coding Calendar, Codeforces

Answer 5

https://en.m.wikipedia.org/wiki/Competitive_programming