Compilare: user.cpp: In function ‘void buildpi(std::string)’: user.cpp:19:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1 ; i < p.size() ; ++ i) { ^ user.cpp: In function ‘int main()’: user.cpp:39:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < s.size() ; ++ i) { ^ user.cpp:44:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k + 1 == st.size()) { ^ user.cpp:52:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < s.size() ; ++ i) { ^ user.cpp:58:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k + 1 == dr.size()) { ^ user.cpp:53:27: warning: array subscript is below array bounds [-Warray-bounds] match[i] += match[i - 1]; ^