Compilare: main.cpp: In function 'void fa(int, int)': main.cpp:13:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<w[x].size(); i++)fa(w[x][i],t); ~^~~~~~~~~~~~ main.cpp: In function 'void fb(int, int)': main.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[x].size(); i++)fb(v[x][i],t); ~^~~~~~~~~~~~