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:69:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<n.size(); i++) ^ user.cpp:73:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1; j<n.size(); j++) ^