Compilare: user.cpp: In function ‘void df(int)’: user.cpp:32:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a[nod].size(); ++i) ^ user.cpp: In function ‘void read()’: user.cpp:16:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &n, &m); ^ user.cpp:21:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &x, &y); ^