public E min() {
BinaryTreeNodeImpl<E> current = root;
while (current.getLeft() != null) {
current = (BinaryTreeNodeImpl<E>) current.getLeft();
}
return current.getData();
}
private BinaryTreeNodeImpl<E> successor(BinaryTreeNodeImpl<E> subroot) {
BinaryTreeNodeImpl<E> current = (BinaryTreeNodeImpl<E>) subroot.getRight();
if (current == null) {
throw new NoSuchElementException();
}
while (current.getLeft() != null) {
current = (BinaryTreeNodeImpl<E>) current.getLeft();
}
return current;
}
private void add(BinaryTreeNodeImpl<E> node, BinaryTreeNodeImpl<E> subroot) {
if (c.compare(node.getData(), subroot.getData()) == 0) {
return; // element found; no duplicate added
}
if (c.compare(node.getData(), subroot.getData()) < 0) {
if (subroot.getLeft() == null) {
subroot.setLeft(node);
node.setParent(subroot);
return;
} else {
add(node, (BinaryTreeNodeImpl<E>) subroot.getLeft());
}
} else {
if (subroot.getRight() == null) {
subroot.setRight(node);
node.setParent(subroot);
return;
} else {
add(node, (BinaryTreeNodeImpl<E>) subroot.getRight());
}
}
}
private boolean contains(BinaryTreeNodeImpl<E> node, BinaryTreeNodeImpl<E> subroot) {
count++;
if (subroot == null) {
return false;
}
if (c.compare(node.getData(), subroot.getData()) == 0) {
return true;
}
if (c.compare(node.getData(), subroot.getData()) < 0) {
return contains(node, (BinaryTreeNodeImpl<E>) subroot.getLeft());
} else {
return contains(node, (BinaryTreeNodeImpl<E>) subroot.getRight());
}
}
private void remove(BinaryTreeNodeImpl<E> node, BinaryTreeNodeImpl<E> subroot) {
if (subroot == null) { // element not present
return;
}
if (c.compare(node.getData(), subroot.getData()) == 0) { // element found
if (subroot.getLeft() == null && subroot.getRight() == null) { // no children
if (subroot == root) {
root = null;
} else if (subroot.getParent().getLeft() == subroot) {
subroot.getParent().setLeft(null);
} else {
subroot.getParent().setRight(null);
}
} else if (subroot.getLeft() == null) { // right child only
BinaryTreeNodeImpl<E> successor = successor(subroot);
if (successor.getParent() == subroot) {
successor.getParent().setRight(null);
} else {
successor.getParent().setLeft(null);
}
if (subroot == root) {
root = successor;
successor.setParent(null);
} else {
successor.setParent(subroot.getParent());
if (subroot.getParent().getLeft() == subroot) {
successor.getParent().setLeft(successor);
} else {
successor.getParent().setRight(successor);
}
}
successor.setRight(subroot.getRight());
if (successor.getRight() != null) {
successor.getRight().setParent(successor);
}
} else if (subroot.getRight() == null) { // left child only
// get predecessor
BinaryTreeNodeImpl<E> predecessor = predecessor(subroot);
// remove predecessor's parent's link to it
if (predecessor.getParent() == subroot) {
predecessor.getParent().setLeft(null);
} else {
predecessor.getParent().setRight(null);
}
// set predecessor's link to its new parent, if applicable
if (subroot == root) {
root = predecessor;
predecessor.setParent(null);
} else {
predecessor.setParent(subroot.getParent());
// and set reciprocating link from parent to predecessor
if (subroot.getParent().getLeft() == subroot) {
predecessor.getParent().setLeft(predecessor);
} else {
predecessor.getParent().setRight(predecessor);
}
}
// set predecessor's new left child (right remains null)
predecessor.setLeft(subroot.getLeft());
if (predecessor.getLeft() != null) {
predecessor.getLeft().setParent(predecessor);
}
} else { // two children
BinaryTreeNodeImpl<E> successor = successor(subroot);
if (successor.getParent() == subroot) {
successor.getParent().setRight(null);
} else {
successor.getParent().setLeft(null);
}
if (subroot == root) {
root = successor;
successor.setParent(null);
} else {
successor.setParent(subroot.getParent());
if (subroot.getParent().getLeft() == subroot) {
successor.getParent().setLeft(successor);
} else {
successor.getParent().setRight(successor);
}
}
successor.setLeft(subroot.getLeft());
successor.getLeft().setParent(successor);
successor.setRight(subroot.getRight());
if (successor.getRight() != null) {
successor.getRight().setParent(successor);
}
}
return;
}
if (c.compare(node.getData(), subroot.getData()) < 0) { // element not yet found, go left
remove(node, (BinaryTreeNodeImpl<E>) subroot.getLeft());
} else { // element not yet found, go right
remove(node, (BinaryTreeNodeImpl<E>) subroot.getRight());
}
}