Compilare: user.cpp: In function ‘int check(VI)’: user.cpp:46:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<a.size(); ++i) ^ user.cpp: In function ‘void dfs(int)’: user.cpp:62:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[v].size(); ++i) ^ user.cpp: In function ‘void read()’: user.cpp:105:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1; j<rs[i].size(); ++j) ^