Compilare: user.cpp: In function ‘void upd_a(int&)’: user.cpp:63:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (G[a].size() == n - 1) ^ user.cpp: In function ‘int main()’: user.cpp:114:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:119:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^