二叉搜索树的中序遍历排序

package org.exam.ch8;

/**
* Created by xin on 15.10.14.
*/
class Node{
public int iData;
public double dData;
public Node leftChild;
public Node rightChild;
@Override
public String toString() {
return "Node{" +
"iData=" + iData +
", dData=" + dData +
'}';
}
}
class Tree{
private Node root;
public Node find(int key){
Node current=root;
while (current.iData!=key){
if (key<current.iData){
current=current.leftChild;
}else{
current=current.rightChild;
}
}
if (current==null){
return null;
}
return current;
}
public void insert(int iData,double dData){
Node newNode=new Node();
newNode.iData=iData;
newNode.dData=dData;
if (root==null){
root=newNode;
}else{
Node current=root;
Node parent=null;
while (true){
parent=current;
if (iData<current.iData){
current=current.leftChild;
if (current==null){
parent.leftChild=newNode;
return;
}
}else{
current=current.rightChild;
if (current==null){
parent.rightChild=newNode;
return;
}
}
}
}
}
public void traverse(int traverseType){
switch(traverseType){
case 1: System.out.print("\nPreorder traversal: ");
preOrder(root);
break;
case 2: System.out.print("\nInorder traversal:  ");
inOrder(root);
break;
case 3: System.out.print("\nPostorder traversal: ");
postOrder(root);
break;
}
System.out.println();
}
private void preOrder(Node localRoot){
if (localRoot!=null){
System.out.print(localRoot.iData + " ");
inOrder(localRoot.leftChild);
inOrder(localRoot.rightChild);
}
}
private void inOrder(Node localRoot){
if (localRoot!=null){
inOrder(localRoot.leftChild);
System.out.print(localRoot.iData+" ");
inOrder(localRoot.rightChild);
}
}
private void postOrder(Node localRoot){
if (localRoot!=null){
inOrder(localRoot.leftChild);
inOrder(localRoot.rightChild);
System.out.print(localRoot.iData+" ");
}
}
public Node minimum(){
Node current=root;
while (current!=null){
if (current.leftChild==null){
return current;
}else{
current=current.leftChild;
}
}
return current;
}
public Node maximum(){
Node current=root;
while (current!=null){
if (current.rightChild==null){
return current;
}else{
current=current.rightChild;
}
}
return current;
}
public boolean delete(int key){
Node current=root;
Node parent=null;
boolean isLeftChild=false;//找到的节点不是根时(所以初如化时真假亦可),isLeftChild指的是current是不是parent的左子节点.
while (current.iData!=key){
parent=current;
if (key<current.iData){
isLeftChild=true;
current=current.leftChild;
}else{
isLeftChild=false;
current=current.rightChild;
}
if (current==null){//没有找到要删除的节点
return false;
}
}
//走到这里表明已找到的节点正是current所指向的节点
if (current.leftChild==null&¤t.rightChild==null){//是叶节点,即没有左右子节点
if (current==root){//如果找到的是根,设为null即可,
root=null;
}else if (isLeftChild){//如果找到的是一个节点的左子节点,那么将这个节点的左子节点设为null
parent.leftChild=null;
}else {//同理,如果找到的是一个节点的右子节点，那么将这个节点的右子节点设为null即可.
parent.rightChild=null;
}
}else if (current.rightChild==null){//左子节点不存在,右子节点存在
if (current==root){
root=current.leftChild;
}else if (isLeftChild){
parent.leftChild=current.leftChild;
}else{
parent.rightChild=current.leftChild;
}
}else if (current.leftChild==null){//左子节点存在,右子节点不存在
if (current==root){
root=current.rightChild;
}else if (isLeftChild){
parent.leftChild=current.rightChild;
}else{
parent.rightChild=current.rightChild;
}
}else{//左右子节点都存在
Node successor=getSuccessor(current);//找一个比删除节点大得最少的一个节点(当然我认为找一个比删除节点小得最少的一个节点也可以)作为后继节点
if (current==root){
root=successor;
}else if (isLeftChild){
parent.leftChild=successor;
}else{
parent.rightChild=successor;
}
successor.leftChild=current.leftChild;//后继节点左子节点连接原删除节点的左子节点;后继节点右子节点连接在getSuccessor已处理(删除后,当然后继节点的右子节点也可能不存在)
}
return true;
}
private Node getSuccessor(Node delNode) {
Node successorParent=delNode;
Node successor=null;
Node current=delNode.rightChild;//从删除节点的右子节点开始找
while (current!=null){
successorParent=successor;//将successor的父节点使用successorParent缓存下来
successor=current;//先将最后找到的节点缓存下来
current=current.leftChild;//往左子节点找,直到左子点为null时,停止查找
}
//此时的current一定为null,successor就是后继节点.如果后继节点正是删除节点的右子节点，就返回处理即可;否则,先处理好这个断掉的后继节点
if (successor!=delNode.rightChild){
successorParent.leftChild=successor.rightChild;
successor.rightChild=delNode.rightChild;
}
return successor;
}
}
public class TreeApp {
public static void main(String[] args) {
Tree tree=new Tree();
tree.insert(50,1.5);
tree.insert(25,1.7);
tree.insert(75,1.9);
tree.insert(15,1.3);
tree.insert(17,1.1);
tree.insert(35,2.9);
tree.insert(54,3.2);

/*
Node found=tree.find(25);
if (found != null) {
System.out.println("Found the node with key 25");
}else{
System.out.println("Couldn't find node with key 25");
}
System.out.println("maximum = " + tree.maximum());
System.out.println("minimum = " + tree.minimum());
*/
tree.traverse(2);

}
}