Compilare: user.cpp: In function ‘void build_Z_array()’: user.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < str.size(); ++i) ^ user.cpp:23:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(R < str.size() && str[R - L] == str[R]) ^ user.cpp:36:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(R < str.size() && str[R - L] == str[R]) ^ user.cpp: In function ‘int main()’: user.cpp:55:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = P.size() + 1; i < str.size(); ++i) ^ user.cpp:56:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(Z[i] == P.size()) ^