View Compilation Error

0_0_32717669_12556.cpp: In function 'bool operator<(node, node)':
0_0_32717669_12556.cpp:12:19: error: request for member 'nx' in 'n', which is of non-class type 'int'
  return a.nx == n.nx ? a.v < b.v : a.nx > b.nx;
                   ^