private BSTVertex rotateLeft(BSTVertex T) {
BSTVertex w = T.right;
// Connect the right node of T (which is w) to the parent of T
w.parent = T.parent;
// Put w above T
T.parent = w;
// Left node of w is shifted to right of T to replace w
T.right = w.left;
// Need to set the parent of w.left unless w.left does not exist
if (w.left != null) {
w.left.parent = T;
}
// Set T, which is under w, to w.left
w.left = T;
if (w.parent != null) {
if (w.parent.left == T) {
w.parent.left = w;
} else {
w.parent.right = w;
}
}
updateHeight(T);
updateHeight(w);
// Only T and w has new sizes
w.size = T.size;
T.size = getSize(T.left) + getSize(T.right) + 1;
return w;
}
private BSTVertex rotateRight(BSTVertex T) {
BSTVertex w = T.left;
w.parent = T.parent;
T.parent = w;
T.left = w.right;
if (w.right != null) {
w.right.parent = T;
}
w.right = T;
if (w.parent != null) {
if (w.parent.left == T) {
w.parent.left = w;
} else {
w.parent.right = w;
}
}
updateHeight(T);
updateHeight(w);
w.size = T.size;
T.size = getSize(T.left) + getSize(T.right) + 1;
return w;
}