Algorithms

mynode *closestAncestor(mynode* root, mynode* p, mynode* q)
{
   mynode *l, *r, *tmp;

   if(root == NULL)
   {
      return(NULL);
   }

 if(root->left==p || root->right==p || root->left==q || root->right==q)

   {
     return(root);
   }
   else
   {
      l = closestAncestor(root->left, p, q);
      r = closestAncestor(root->right, p, q);

      if(l!=NULL && r!=NULL)
      {
        return(root);
      }
      else
      {
         tmp = (l!=NULL) ? l : r;
         return(tmp);
      }
   }
}

int closestanc(node * root, int n1, int n2)
{
    int l, r;
    if(root == NULL)
    return -1;
    if(root->right->data == n1 || root->right->data == n2 || root->left->data == n1 || root->left->data == n2)
    return root->data;
    else
    {
        l = closestanc(root->left, n1, n2);
        r = closestanc(root->right, n1, n2);
        if(l!= -1 && r!= -1)
        return root->data;
        else
        return (l != -1 ? l : r);
    }
}