Compilare: user.cpp: In function ‘void read()’: user.cpp:20:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &n , &m ) ; ^ user.cpp:23:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&x) ; ^ user.cpp: In function ‘void solve()’: user.cpp:67:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &x , &y ) ; ^ user.cpp: In function ‘int main()’: user.cpp:87:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("lca.in","r",stdin); ^ user.cpp:88:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("lca.out","w",stdout); ^