Compilare: main.cpp: In function 'int main()': main.cpp:22:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arbori.in","r",stdin); ^ main.cpp:23:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arbori.out","w",stdout); ^ main.cpp:24:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld",&n,&m,&k); ^