View Compilation Error

0_0_22598512_24850.cpp: In function 'void cal(int)':
0_0_22598512_24850.cpp:113:39: error: invalid initialization of non-const reference of type 'std::__detail::_Node_iterator<std::pair<const long long int, int>, false, false>&' from an rvalue of type 'std::unordered_map<long long int, int>::iterator {aka std::__detail::_Node_iterator<std::pair<const long long int, int>, false, false>}'
    auto &it = hash.find(k*inv[d] % MOD);
                                       ^