Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[varf].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:62:11: warning: left operand of comma operator has no effect [-Wunused-value] a,b; ^ user.cpp:62:12: warning: right operand of comma operator has no effect [-Wunused-value] a,b; ^