Compilare: user.cpp: In instantiation of ‘int RMQ<ForwardIterator, Function>::iQuery(int, int) [with ForwardIterator = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; Function = std::function<bool(int, int)>]’: user.cpp:49:24: required from ‘RMQ<ForwardIterator, Function>::T RMQ<ForwardIterator, Function>::vQuery(int, int) [with ForwardIterator = __gnu_cxx::__normal_iterator<int*, std::vector<int> >; Function = std::function<bool(int, int)>; RMQ<ForwardIterator, Function>::T = int]’ user.cpp:73:37: required from here user.cpp:40:13: warning: unused variable ‘l’ [-Wunused-variable] int l = M[begin][step]; ^ user.cpp:41:13: warning: unused variable ‘mid’ [-Wunused-variable] int mid = end - (1<<step) + 1; ^~~ user.cpp:42:13: warning: unused variable ‘r’ [-Wunused-variable] int r = M[end - (1<<step) + 1][step]; ^ user.cpp: In function ‘int main()’: user.cpp:80:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rmq.in", "r", stdin); ^ user.cpp:81:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rmq.out", "w", stdout); ^