Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:16:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a[x].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:26:13: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k,x,y; ^