foo.cc: In function ‘int search(Node)’:
foo.cc:135:1: warning: control reaches end of non-void function [-Wreturn-type]
  135 | }
      | ^
foo.cc: In function ‘int main()’:
foo.cc:141:10: warning: iteration 9 invokes undefined behavior [-Waggressive-loop-optimizations]
  141 | hashs[i] = hashs[i-1] * i;
      | ~~~~~~~~~^~~~~~~~~~~~~~~~
foo.cc:140:14: note: within this loop
  140 | for(int i=1;i<11;i++){
      |             ~^~~