Compilare: user.cpp: In function ‘int main()’: user.cpp:57:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 1; i < sol.size(); i++ ) ^ user.cpp:59:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < sol.size(); i++ ) ^