Compilare: user.cpp: In function ‘void precompute()’: user.cpp:19:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 3; i <= s.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:33:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++) ^ user.cpp:39:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s.size() - 1 - c || i == s.size() - 2 - c) ^ user.cpp:39:61: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s.size() - 1 - c || i == s.size() - 2 - c) ^