Compilare: user.cpp: In function ‘int main()’: user.cpp:85:7: warning: unused variable ‘proxynode’ [-Wunused-variable] int proxynode = -1; ^~~~~~~~~ user.cpp:52:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:55:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^