/in/foo.cc: In function 'void Bfs()':
/in/foo.cc:58:49: error: no matching function for call to 'maze::maze(<brace-enclosed initializer list>)'
                 q.push(maze{tx, ty, tmp.step + 1});
                                                 ^
/in/foo.cc:19:8: note: candidate: maze::maze()
 struct maze
        ^~~~
/in/foo.cc:19:8: note:   candidate expects 0 arguments, 3 provided
/in/foo.cc:19:8: note: candidate: constexpr maze::maze(const maze&)
/in/foo.cc:19:8: note:   candidate expects 1 argument, 3 provided
/in/foo.cc:19:8: note: candidate: constexpr maze::maze(maze&&)
/in/foo.cc:19:8: note:   candidate expects 1 argument, 3 provided