Compilare: user.cpp: In function ‘int BFS(int)’: user.cpp:31:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[x].size();++i) ^ user.cpp: In function ‘void update(int)’: user.cpp:43:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:100:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[1].size(); ++i) ^ user.cpp:104:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[1].size(); ++i) ^