package com.circle.collection;
/**
* Created by keweiyang on 2017/2/25.
* 自定义二叉树
*/
public class BinaryTree {
private Node root;
/**
* 查找某个节点
*
* @param key
* @return
*/
public Node get(int key) {
Node currentNode = root;
if (currentNode == null) {
throw new RuntimeException("这棵二叉树为空二叉树");
} else {
while (currentNode.getId()!= key) {
if (currentNode.getId() > key) {
currentNode = currentNode.getLeftChild();
} else {
currentNode.getRightChild();
}
if (currentNode == null) {
return null;
}
}
}
return currentNode;
}
/**
* 插入一个节点
*
* @param id
* @param data
*/
public void insert(int id, Object data) {
Node newNode = new Node(id, data);
//1:先找到插入位置
Node parentNode = null;
Node currentNode = root;
if (root == null) {
root = newNode;
} else {
while (true) {
parentNode = currentNode;
if (currentNode.getId() > id) {
currentNode = currentNode.getLeftChild();
if (currentNode == null) {
//如果没有左子节点，则插入
parentNode.setLeftChild(newNode);
return;
}
} else {
currentNode = currentNode.getRightChild();
if (currentNode == null) {
//如果没有右子节点，则插入
parentNode.setRightChild(newNode);
return;
}
}
}
}
}
/**
* 删除节点
* @param key
*/
public boolean delete(int key) {
//根据key找到对应的节点
// 1、如果该节点不存在就抛出异常
Node parentNode = null;
Node currentNode = root;
boolean isLeftNode = false;
if (currentNode == null) {
throw new RuntimeException("二叉树为空");
}else{
while (currentNode.getId() != key) {
parentNode = currentNode;
if (currentNode.getId() < key) {
currentNode = currentNode.getRightChild();
isLeftNode = false;
}else{
currentNode = currentNode.getLeftChild();
isLeftNode = true;
}
if (currentNode == null) {
return false;
}
}
}
//2、下面讨论该节点存在
// 2.1如果该节点的左右子节点都不存在，则直接删除该节点
if (currentNode.getRightChild() == null && currentNode.getLeftChild() == null) {
this.noChild(currentNode, parentNode, isLeftNode);
}
// 2.2如果该节点的只存在一个子节点
//2.2.1 如果存在左节点
if (currentNode.getRightChild() == null) {
this.oneLeftChild(currentNode,parentNode,isLeftNode);
}
//2.2.2 如果存在右节点
if (currentNode.getLeftChild() == null) {
this.oneRightChild(currentNode, parentNode, isLeftNode);
}
//2.3 如果左右孩子都存在，则直接拿右孩子中最小的节点替换该节点
if (currentNode.getLeftChild() != null && currentNode.getRightChild() != null) {
this.bothChild(currentNode, parentNode, isLeftNode);
}
return false;
}
private void bothChild(Node currentNode, Node parentNode, boolean flag) {
//找到中序后继节点
if (flag) {
Node node = this.successor(currentNode);
node.setLeftChild(currentNode.getLeftChild());
parentNode.setLeftChild(node);
}else{
Node node = this.successor(currentNode);
node.setRightChild(currentNode.getRightChild());
parentNode.setRightChild(node);
}
}
private Node successor(Node currentNode) {
//由于当前节点的左右子节点都存在，所以current一定存在
Node parent = currentNode;
Node current = currentNode.getRightChild();
while (current != null) {
parent = current;
current = current.getLeftChild();
}
return parent;
}
private void oneRightChild(Node currentNode, Node parentNode, boolean flag) {
if (flag) {
parentNode.setRightChild(currentNode.getLeftChild());
}else{
parentNode.setRightChild(currentNode.getRightChild());
}
}
private void oneLeftChild(Node currentNode, Node parentNode, boolean flag) {
if (flag) {
parentNode.setLeftChild(currentNode.getLeftChild());
}else{
parentNode.setLeftChild(currentNode.getRightChild());
}
}
private void noChild(Node currentNode, Node parentNode, boolean flag) {
if (flag) {
parentNode.setLeftChild(null);
}else{
parentNode.setRightChild(null);
}
}
/**
* 前序
*
* @param node
*/
public void preOrder(Node node) {
if (node != null) {
System.out.println(node.getId() + "--- ");
preOrder(node.getLeftChild());
preOrder(node.getRightChild());
}
}
/**
* 中序
*
* @param node
*/
public void inOrder(Node node) {
if (node != null) {
inOrder(node.getLeftChild());
System.out.println(node.getId() + "--");
inOrder(node.getRightChild());
}
}
/**
* 后序
*
* @param node
*/
public void postOrder(Node node) {
if (node != null) {
postOrder(node.getLeftChild());
postOrder(node.getRightChild());
System.out.println(node.getId() + "---");
}
}
private class Node {
private int id;
private Object data;
private Node leftChild;
private Node rightChild;
public Node(int id, Object data) {
this.id = id;
this.data = data;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public Node getLeftChild() {
return leftChild;
}
public void setLeftChild(Node leftChild) {
this.leftChild = leftChild;
}
public Node getRightChild() {
return rightChild;
}
public void setRightChild(Node rightChild) {
this.rightChild = rightChild;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Override
public String toString() {
return "id= " + id + " , data= " + data;
}
}
}