Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[st].size();i++) ^ user.cpp: In function ‘void cd(int)’: user.cpp:34:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[st].size();i++) ^ user.cpp: In function ‘void cd1(int)’: user.cpp:46:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[st].size();i++) ^