View Compilation Error

0_0_37636404_11840.cpp: In function 'int main()':
0_0_37636404_11840.cpp:73:29: error: no matching function for call to 'hungarian()'
          auto p = hungarian();
                             ^
0_0_37636404_11840.cpp:73:29: note: candidate is:
0_0_37636404_11840.cpp:10:22: note: template<class T> std::pair<T, std::vector<int> > hungarian(const std::vector<std::vector<_RealType> >&)
 pair<T, vector<int>> hungarian(const vector<vector<T>> &a) {
                      ^
0_0_37636404_11840.cpp:10:22: note:   template argument deduction/substitution failed:
0_0_37636404_11840.cpp:73:29: note:   candidate expects 1 argument, 0 provided
          auto p = hungarian();
                             ^