Compilare: user.cpp: In function ‘int main()’: user.cpp:29:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0, j = 0; i < a.size() && j < b.size(); ) ^ user.cpp:29:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0, j = 0; i < a.size() && j < b.size(); ) ^ user.cpp:43:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < sol.size(); ++i ) ^ user.cpp:48:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < a.size(); ++i ) ^