Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:72:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i <= M[el].size()-1; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:28:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &n, &p); ^ user.cpp:33:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &x, &y);//fin >> x >> y; ^