编程语言
首页 > 编程语言> > Java实现:二叉搜索树(Binary Search Tree),突围金九银十面试季

Java实现:二叉搜索树(Binary Search Tree),突围金九银十面试季

作者:互联网

/**

*/

private static class BinaryNode {

BinaryNode(AnyType theElement) {

this(theElement, null, null);

}

BinaryNode(AnyType theElement, BinaryNode left, BinaryNode right) {

element = theElement;

left = left;

right = right;

}

AnyType element; // the data in the node

BinaryNode left; // Left child

BinaryNode right; // Right child

}

1.3、构造器和成员变量

private BinaryNode root;

private Comparator<? super AnyType> cmp;

/**

*/

public BinarySearchTree() {

this(null);

}

/**

*/

public BinarySearchTree(Comparator<? super AnyType> c) {

root = null;

cmp = c;

}

1.3、公共方法(public method)

主要包括插入,删除,找到最大值、最小值,清空树,查看元素是否包含;

/**

*/

public void makeEmpty() {

root = null;

}

public boolean isEmpty() {

return root == null;

}

public boolean contains(AnyType x){

return contains(x,root);

}

public AnyType findMin(){

if (isEmpty()) throw new BufferUnderflowException();

return findMin(root).element;

}

public AnyType findMax(){

if (isEmpty()) throw new BufferUnderflowException();

return findMax(root).element;

}

public void insert(AnyType x){

root = insert(x, root);

}

public void remove(AnyType x){

root = remove(x,root);

}

1.4、比较函数

如果有比较器,就使用比较器,否则要求对象实现了Comparable接口;

private int myCompare(AnyType lhs, AnyType rhs) {

if (cmp != null) {

return cmp.compare(lhs, rhs);

} else {

return lhs.compareTo(rhs);

}

}

1.5、contains 函数

本质就是一个树的遍历;

private boolean contains(AnyType x, BinaryNode t) {

if (t == null) {

return false;

}

int compareResult = myCompare(x, t.element);

if (compareResult < 0) {

return contains(x, t.left);

} else if (compareResult > 0) {

return contains(x, t.rig

【一线大厂Java面试题解析+后端开发学习笔记+最新架构讲解视频+实战项目源码讲义】

浏览器打开:qq.cn.hn/FTf 免费领取

ht);

} else {

return true;

}

}

1.6、findMin

因为二叉搜索树的性质,最小值一定是树的最左节点,要注意树为空的情况。

/**

*/

private BinaryNode findMin(BinaryNode t) {

if (t == null) {

return null;

}

if (t.left == null) {

return t;

}

return findMin(t.left);

}

1.7、findMax

最右节点;

/**

*/

private BinaryNode findMax(BinaryNode t){

if (t == null){

return null;

}

if (t.right == null){

return t;

}

return findMax(t.right);

}

1.8、insert

这个主要是根据二叉搜索树的性质,注意当树为空的情况,就可以加入新的节点了,还有当该值已经存在时,默认不进行操作;

/**

*/

private BinaryNode insert(AnyType x, BinaryNode t){

if (t == null){

return new BinaryNode<>(x,null,null);

}

int compareResult = myCompare(x,t.element);

if (compareResult < 0){

t.left = insert(x,t.left);

}

else if (compareResult > 0){

t.right = insert(x,t.right);

}

else{

//Duplicate; do nothing

}

return t;

}

1.9、remove

imgimgimg

注意当空树时,返回null;

最后一个三元表达式,是在之前已经排除掉节点有两个儿子的情况下使用的。

/**

*/

private BinaryNode remove(AnyType x, BinaryNode t){

if (t == null){

return t; // Item not found ,do nothing

}

int compareResult = myCompare(x,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){

//Two children

t.element = findMin(t.right).element;

t.right = remove(t.element,t.right);

}

else

t = (t.left !=null) ? t.left:t.right;

return t;

}

二、完整代码实现(Java)


/**

*/

import com.sun.source.tree.BinaryTree;

import java.nio.BufferUnderflowException;

import java.util.Comparator;

/**

*/

public class BinarySearchTree<AnyType extends Comparable<? super AnyType>> {

/**

*/

private static class BinaryNode {

BinaryNode(AnyType theElement) {

this(theElement, null, null);

}

BinaryNode(AnyType theElement, BinaryNode left, BinaryNode right) {

element = theElement;

left = left;

right = right;

}

AnyType element; // the data in the node

BinaryNode left; // Left child

BinaryNode right; // Right child

}

private BinaryNode root;

private Comparator<? super AnyType> cmp;

/**

*/

public BinarySearchTree() {

this(null);

}

/**

*/

public BinarySearchTree(Comparator<? super AnyType> c) {

root = null;

cmp = c;

}

/**

*/

public void makeEmpty() {

root = null;

}

public boolean isEmpty() {

return root == null;

}

public boolean contains(AnyType x){

return contains(x,root);

}

public AnyType findMin(){

if (isEmpty()) throw new BufferUnderflowException();

return findMin(root).element;

}

public AnyType findMax(){

if (isEmpty()) throw new BufferUnderflowException();

return findMax(root).element;

}

public void insert(AnyType x){

root = insert(x, root);

}

public void remove(AnyType x){

root = remove(x,root);

}

标签:Binary,Search,return,BinaryNode,AnyType,Java,null,root,public
来源: https://blog.csdn.net/m0_63174529/article/details/121278476