Compilare: user.cpp: In function ‘int main()’: user.cpp:33:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v.size(); ++i) ^ user.cpp: In function ‘void BFS(int)’: user.cpp:56:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < M[X[1]].size(); ++i) ^