Compilare: user.cpp: In function ‘void solve1()’: user.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<n.size(); i++) ^ user.cpp: In function ‘void solve2()’: user.cpp:66:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<n.size(); i++) ^ user.cpp:68:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<n.size(); i++) ^ user.cpp:71:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<n.size(); i++) ^