BinarySearchTree 二叉查找树

public class BinarySearchTree<T extends Comparable<? super T>> {public BinarySearchTree() {root = null;}public void insert(T x) {root = insert(x, root);}public void remove(T x) {root = remove(x, root);}public T findMin() {if (isEmpty())throw new RuntimeException();return findMin(root).element;}public T findMax() {if (isEmpty())throw new RuntimeException();return findMax(root).element;}public boolean contains(T x) {return contains(x, root);}public void makeEmpty() {root = null;}public boolean isEmpty() {return root == null;}public void printTree() {if (isEmpty())System.out.println("Empty Tree");elseprintTree(root);}public BinaryNode<T> insert(T x, BinaryNode<T> t) {if (t == null)return new BinaryNode<T>(x, null, null);int compareresult = x.compareTo(t.element);if (compareresult < 0)t.left = insert(x, t.left);else if (compareresult > 0)t.right = insert(x, t.right);else;// Duplicate; do nothingreturn t;}private BinaryNode<T> remove(T x, BinaryNode<T> t) {if (t == null)return t;int compareResult = x.compareTo(t.element);if (compareResult < 0)t.left = remove(x, t.left);else if (compareResult > 0)t.right = remove(x, t.right);else if (t.left != null && t.right != null) {t.element = findMin(t.right).element;t.right = remove(t.element, t.right);} elset = (t.left != null) ? t.left : t.right;return t;}private BinaryNode<T> findMin(BinaryNode<T> t) {if (t == null)return null;else if (t.left == null)return t;elsereturn findMin(t.left);}private BinaryNode<T> findMax(BinaryNode<T> t) {if (t != null)while (t.right != null)t = t.right;return t;}private boolean contains(T x, BinaryNode<T> t) {if (t == null)return false;int compareResult = x.compareTo(t.element);if (compareResult < 0)return contains(x, t.left);else if (compareResult > 0)return contains(x, t.right);elsereturn true;}private void printTree(BinaryNode<T> t) {if (t != null) {printTree(t.left);System.out.println(t.element);printTree(t.right);}}private BinaryNode<T> root;private int height(BinaryNode<T> t) {if (t == null)return -1;elsereturn 1 + Math.max(height(t.left), height(t.right));}private static class BinaryNode<T> {BinaryNode(T theElement) {this(theElement, null, null);}BinaryNode(T theElement, BinaryNode<T> lt, BinaryNode<T> rt) {element = theElement;left = lt;right = rt;}T element;BinaryNode<T> left;BinaryNode<T> right;}public static void main(String[] args) {BinarySearchTree<Integer> t = new BinarySearchTree<Integer>();final int NUMS = 400;final int GAP = 37;System.out.println("Checking... (no more output means success)");for (int i = GAP; i != 0; i = (i + GAP) % NUMS) {t.insert(i);}for (int i = 0; i < NUMS; i += 2) {t.remove(i);}if (NUMS < 40)t.printTree();if (t.findMin() != 2 || t.findMax() != NUMS - 2)System.out.println("FindMin or FindMax error!");for (int i = 2; i < NUMS; i += 2)if (!t.contains(i))System.out.println("Find error1!");for (int i = 1; i < NUMS; i += 2) {if (t.contains(i))System.out.println("Find error2!");}}}