Compilare: user.cpp: In function ‘void df(int)’: user.cpp:22:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[x].size(); ++i) ^ user.cpp:33:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[x].size(); ++i) ^ user.cpp:32:15: warning: ‘z’ may be used uninitialized in this function [-Wmaybe-uninitialized] color[x]=z; ^