/in/foo.cc: In function 'int read()':
/in/foo.cc:10:39: warning: statement has no effect [-Wunused-value]
  while (c>'9' || c<'0') {if (c=='-') f-1; c=getchar();}
                                      ~^~
/in/foo.cc: In member function 'int Treap::rank(int, int)':
/in/foo.cc:100:2: warning: control reaches end of non-void function [-Wreturn-type]
  }
  ^