Compilare: user.cpp: In function ‘void expand()’: user.cpp:19:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<graph[k][nod].size();++i) ^ user.cpp: In function ‘void df(int, int)’: user.cpp:35:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<tree[k][nod].size();++i)df(tree[k][nod][i],nv+1); ^ user.cpp: In function ‘int main()’: user.cpp:60:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<rad.size();++i) ^