@toc
1 前序线索化与前序线索化遍历
1.1 前序线索化二叉树
public void threadedPreNode(HeroNode node) {
if (node == null) {
return;
}
//线索化当前节点
if (node.getLeft() == null) {
node.setLeft(pre);
node.setLeftType(1);
}
if (pre != null && pre.getRight() == null) {
pre.setRight(node);
pre.setRightType(1);
}
pre = node;
//线索化左子树
if (node.getLeftType() != 1) {
threadedPreNode(node.getLeft());
}
//线索化右子树
if (node.getRightType() != 1) {
threadedPreNode(node.getRight());
}
}1.2 前序线索化遍历
public void threadedPreList() {
//定义一个变量，存储当前遍历的结点，从root开始
HeroNode node = root;
while (node != null) {
//打印当前这个结点
System.out.println(node);
while (node.getLeftType() == 0) {
node = node.getLeft();
System.out.println(node);
}
//如果当前结点的右指针指向的是后继结点,就一直输出
while (node.getRightType() == 1) {
//获取到当前结点的后继结点
node = node.getRight();
System.out.println(node);
}
//替换这个遍历的结点
node = node.getRight();
}
}2 完整代码
package edu.seu.demo10tree.demothreadedbinarytree;
public class Demo01ThreadedBinaryTree {
public static void main(String[] args) {
//测试一把中序线索二叉树的功能
HeroNode root = new HeroNode(1, "tom");
HeroNode node2 = new HeroNode(3, "jack");
HeroNode node3 = new HeroNode(6, "smith");
HeroNode node4 = new HeroNode(8, "mary");
HeroNode node5 = new HeroNode(10, "king");
HeroNode node6 = new HeroNode(14, "dim");
//二叉树，后面我们要递归创建, 现在简单处理使用手动创建
root.setLeft(node2);
root.setRight(node3);
node2.setLeft(node4);
node2.setRight(node5);
node3.setLeft(node6);
//测试中序线索化 8, 3, 10, 1, 14, 6
ThreadedBinaryTree threadedBinaryTree = new ThreadedBinaryTree();
threadedBinaryTree.setRoot(root);
// threadedBinaryTree.threadedNode();
// 中序 8, 3, 10, 1, 14, 6
// HeroNode leftNode = node5.getLeft();
// HeroNode rightNode = node5.getRight();
// System.out.println("10号结点的前驱结点是=" + leftNode); //3
// System.out.println("10号结点的后继结点是=" + rightNode); //1
// System.out.println("使用线索化的方式遍历 线索化二叉树");
// threadedBinaryTree.threadedList();
// 前序 1,3,8,10,6,14
threadedBinaryTree.threadedPreNode(root);
HeroNode leftNode = node5.getLeft();
HeroNode rightNode = node5.getRight();
System.out.println("10号结点的前驱结点是=" + leftNode);
System.out.println("10号结点的后继结点是=" + rightNode);
System.out.println("使用线索化的方式遍历 线索化二叉树");
threadedBinaryTree.threadedPreList();
}
}
class HeroNode {
private int no;//英雄编号
private String name;//姓名
private HeroNode left;//左子节点
private HeroNode right;//右子节点
private int rightType;//表示右子节点：指针：0，后继：1
private int leftType;//表示左子节点：指针：0 前驱：1
public int getRightType() {
return rightType;
}
public void setRightType(int rightType) {
this.rightType = rightType;
}
public int getLeftType() {
return leftType;
}
public void setLeftType(int leftType) {
this.leftType = leftType;
}
//构造方法
public HeroNode(int no, String name) {
this.no = no;
this.name = name;
}
//读取与设置私有变量
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public HeroNode getLeft() {
return left;
}
public void setLeft(HeroNode left) {
this.left = left;
}
public HeroNode getRight() {
return right;
}
public void setRight(HeroNode right) {
this.right = right;
}
//打印输出
@Override
public String toString() {
return "HeroNode{" +
"no=" + no +
", name='" + name + '\'' +
'}';
}
//前序遍历
public void preOrder() {
System.out.println(this);//1.输出父节点
if (this.getLeft() != null) {//2.向左遍历
this.getLeft().preOrder();
}
if (this.getRight() != null) {//3.向右遍历
this.getRight().preOrder();
}
}
//中序遍历
public void infixOrder() {
if (this.getLeft() != null) {
this.getLeft().infixOrder();
}
System.out.println(this);
if (this.getRight() != null) {//3.向右遍历
this.getRight().infixOrder();
}
}
//后序遍历
public void postOrder() {
if (this.getLeft() != null) {
this.getLeft().postOrder();
}
if (this.getRight() != null) {//3.向右遍历
this.getRight().postOrder();
}
System.out.println(this);
}
//前序遍历查找
public HeroNode preOrderSearch(int no) {
System.out.println("前序查找比较次数");
if (this.getNo() == no) {
return this;
}
HeroNode resHero = null;
if (this.left != null) {
resHero = this.left.preOrderSearch(no);
}
if (resHero != null) {
return resHero;
}
if (this.right != null) {
resHero = this.right.preOrderSearch(no);
}
return resHero;
}
//中序遍历查找
public HeroNode infixOrderSearch(int no) {
HeroNode resHero = null;
if (this.left != null) {
resHero = this.left.infixOrderSearch(no);
}
if (resHero != null) {
return resHero;
}
System.out.println("中序查找比较次数");
if (this.getNo() == no) {
return this;
}
if (this.right != null) {
resHero = this.right.infixOrderSearch(no);
}
return resHero;
}
//后序遍历查找
public HeroNode postOrderSearch(int no) {
HeroNode resHero = null;
if (this.left != null) {
resHero = this.left.postOrderSearch(no);
}
if (resHero != null) {
return resHero;
}
if (this.right != null) {
resHero = this.right.postOrderSearch(no);
}
if (resHero != null) {
return resHero;
}
System.out.println("后序查找比较次数");
if (this.getNo() == no) {
return this;
}
return resHero;
}
//删除节点
public void delHeroNode(int no) {
if (this.left != null && this.left.getNo() == no) {
this.left = null;
return;
}
if (this.right != null && this.right.getNo() == no) {
this.right = null;
return;
}
if (this.left != null) {
this.left.delHeroNode(no);
}
if (this.right != null) {
this.right.delHeroNode(no);
}
}
}
class ThreadedBinaryTree {
private HeroNode root;//根节点
private HeroNode pre = null;
public ThreadedBinaryTree() {
}
public void threadedNode() {
threadedNode(root);
}
//中序遍历线索化二叉树的方法
public void threadedList() {
//定义一个变量，存储当前遍历的结点，从root开始
HeroNode node = root;
while (node != null) {
//循环的找到leftType == 1的结点，第一个找到就是8结点
//后面随着遍历而变化,因为当leftType==1时，说明该结点是按照线索化
//处理后的有效结点
while (node.getLeftType() == 0) {
node = node.getLeft();
}
//打印当前这个结点
System.out.println(node);
//如果当前结点的右指针指向的是后继结点,就一直输出
while (node.getRightType() == 1) {
//获取到当前结点的后继结点
node = node.getRight();
System.out.println(node);
}
//替换这个遍历的结点
node = node.getRight();
}
}
//中序线索化二叉树
public void threadedNode(HeroNode node) {
if (node == null) {
return;
}
//线索化左子树
threadedNode(node.getLeft());
//线索化当前节点
if (node.getLeft() == null) {
node.setLeft(pre);
node.setLeftType(1);
}
if (pre != null && pre.getRight() == null) {
pre.setRight(node);
pre.setRightType(1);
}
pre = node;
//线索化右子树
threadedNode(node.getRight());
}
//前序线索化二叉树
public void threadedPreNode(HeroNode node) {
if (node == null) {
return;
}
//线索化当前节点
if (node.getLeft() == null) {
node.setLeft(pre);
node.setLeftType(1);
}
if (pre != null && pre.getRight() == null) {
pre.setRight(node);
pre.setRightType(1);
}
pre = node;
//线索化左子树
if (node.getLeftType() != 1) {
threadedPreNode(node.getLeft());
}
//线索化右子树
if (node.getRightType() != 1) {
threadedPreNode(node.getRight());
}
}
//前序线索化遍历
public void threadedPreList() {
//定义一个变量，存储当前遍历的结点，从root开始
HeroNode node = root;
while (node != null) {
//打印当前这个结点
System.out.println(node);
while (node.getLeftType() == 0) {
node = node.getLeft();
System.out.println(node);
}
//如果当前结点的右指针指向的是后继结点,就一直输出
while (node.getRightType() == 1) {
//获取到当前结点的后继结点
node = node.getRight();
System.out.println(node);
}
//替换这个遍历的结点
node = node.getRight();
}
}
public HeroNode getRoot() {
return root;
}
public void setRoot(HeroNode root) {
this.root = root;
}
//前序遍历
public void preOrder() {
if (this.root != null) {
this.root.preOrder();
} else {
System.out.println("二叉树为空");
}
}
//中序遍历
public void infixOrder() {
if (this.root != null) {
this.root.infixOrder();
} else {
System.out.println("二叉树为空");
}
}
//后序遍历
public void postOrder() {
if (this.root != null) {
this.root.postOrder();
} else {
System.out.println("二叉树为空");
}
}
//前序遍历查找
public HeroNode preOrderSearch(int no) {
if (root != null) {
return root.preOrderSearch(no);
} else {
return null;
}
}
//中序遍历查找
public HeroNode infixOrderSearch(int no) {
if (root != null) {
return root.infixOrderSearch(no);
} else {
return null;
}
}
//后序遍历查找
public HeroNode postOrderSearch(int no) {
if (root != null) {
return this.root.postOrderSearch(no);
} else {
return null;
}
}
//删除节点
public void delHeroNode(int no) {
if (root != null) {
if (root.getNo() == no) {
root = null;
} else {
root.delHeroNode(no);
}
} else {
System.out.println("二叉树为空");
}
}
}
