Let x and y with x $<$ y be two keys in a sequence of keys and suppose that there is

no key that is between them $($in terms of ordering$)$ we say that y is a successor of x$.$

Consider the binary search tree that corresponds to this sequence. Show that either the

node that contains x is an ancestor of the node that contains y or the node that contains

y is an ancestor of the node that contains x$.$

$1$