Compilare: user.cpp: In function ‘bool cond(int)’: user.cpp:13:69: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return (marked[nod]==1 && (val[nod]==0 || val[nod]>un[nod].size())); ^ user.cpp: In function ‘void mark(int)’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0; k<v[nod].size(); k++) ^ user.cpp: In function ‘int main()’: user.cpp:47:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0; k<v[x].size(); k++) ^ user.cpp:52:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<v[x].size(); k++) ^ user.cpp:61:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<ans.size(); i++) ^