/in/foo.cc: In function 'int main()':
/in/foo.cc:55:35: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return deep[x]+deep[y]-2*deep[lca(x,y)];
                                ~~~^~~~~
/in/foo.cc:78:7: note: 'pos' was declared here
   int pos;
       ^~~