find successor in AVL tree

Question

there is avl tree with nodes, and each node has only 3 fields:

1.right child

2.left child

3.value(key)

notice that it doesnt have such field "parrent" or "father". my question is: in case we want to know the successor of EVERY node in the tree, and without use any LinkedList or any collection, what is the method to do so?

Answer 1

You could do something like this

// Returns the last node in the inorder traversal of tree,
// or prev if tree is null.
Node printSuccessors(Node tree, Node prev) {
  if (tree == null) {
    return prev;
  }
  Node lastLeft = printSuccessors(tree.leftChild(), prev);
  if (lastLeft != null) {
    System.out.println("The successor of " + lastLeft.key() 
      + " is " + tree.key());
  }
  return printSuccessors(tree.rightChild(), tree);
}

and then call printSuccessors(root, null) .