Compilare: user.cpp: In function ‘int main()’: user.cpp:124:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < st.size() ; i = i+2 ) ^ user.cpp:132:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < dr.size() ; i = i+2 ) ^ user.cpp:138:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < both.size() ; i++ ) ^ user.cpp:141:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < sol.size() ; i++ ) ^