/in/foo.cc: In member function 'bool Node::operator<(const Node&) const':
/in/foo.cc:6:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   return(a<rdgs.a||a==rdgs.a&&b<rdgs.b);
                    ~~~~~~~~~^~~~~~~~~~
/in/foo.cc: In function 'bool cmp(Node, Node)':
/in/foo.cc:10:16: error: 'struct Node' has no member named 'ax'; did you mean 'a'?
  return (x.a<y.ax)&&(x.b<y.b);
                ^~