If you see #include <bits/stdc++.h>, this is not a standard header. You see this often in competitive programming posts.
You may have trouble compiling your code as a result. The solution is to add a stdc++.h– see https://gist.github.com/galois17/19e9adf84cce9fd2b8c6d9b2d4864e70 – into a bits/ folder in your header search path like /usr/local/include/.