Compilare: user.cpp:55:32: warning: integer constant is so large that it is unsigned [enabled by default] long long S=0,BestSum=-9223372036854775808; ^ user.cpp: In function ‘void DFS(int)’: user.cpp:33:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘bool exist(int, int)’: user.cpp:40:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[f].size(); ++i) ^