Compilare: user.cpp: In function ‘int BFS(int)’: user.cpp:25:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:89:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[1].size(); ++i) ^ user.cpp:93:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[1].size(); ++i) ^