prog.cpp: In function ‘int main()’:
prog.cpp:5:36: error: no type named ‘value_type’ in ‘struct std::greater<int>’
std::priority_queue<int, std::greater<int> >> nodes;
^~~~~~~~~~~~
prog.cpp:5:36: error: template argument 3 is invalid
prog.cpp:5:49: error: expected unqualified-id before ‘>’ token
std::priority_queue<int, std::greater<int> >> nodes;
^~