Function: APPLY-LEFT-ROTATIONS

Source

(defun apply-left-rotations (node)
  (when node
    (when-bind right (right node)
      (when (> (height-diff node) 1)
	(if (< (node-height (right right)) (node-height (left right)))
	    (setf node (double-rotate-left node))
	    (setf node (single-rotate-left node)))))
    node))