Compilare: user.cpp: In function ‘int build(int)’: user.cpp:16:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); i++) ^ user.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:59:19: warning: ‘nod’ may be used uninitialized in this function [-Wmaybe-uninitialized] build(nod); ^