Compilare: main.cpp: In function 'int main()': main.cpp:66:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("perm.in" , "r" , stdin); ^ main.cpp:67:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("perm.out" , "w" , stdout); ^ main.cpp:69:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld" , &n , &k); ^