线索二叉树

节点类。

因为不会使用java的enum。所以RTag和LTag就使用String凑活用吧。

package struct;

public class BiThrNode {
    private String data;
    private BiThrNode lchild;
    private BiThrNode rchild;
    private String LTag;   //Thread或null
    private String RTag;
    public String getData() {
        return data;
    }
    public void setData(String data) {
        this.data = data;
    }
    public BiThrNode getLchild() {
        return lchild;
    }
    public void setLchild(BiThrNode lchild) {
        this.lchild = lchild;
    }
    public BiThrNode getRchild() {
        return rchild;
    }
    public void setRchild(BiThrNode rchild) {
        this.rchild = rchild;
    }
    public String getLTag() {
        return LTag;
    }
    public void setLTag(String lTag) {
        LTag = lTag;
    }
    public String getRTag() {
        return RTag;
    }
    public void setRTag(String rTag) {
        RTag = rTag;
    }
    
}

二叉树线索化及中序遍历的方法。

以及演示代码：

package demo;

import struct.BiThrNode;

public class BiThrTree {
    //pre为全局变量
    public static BiThrNode pre;
    //中序遍历线索化
    public static void InThreading(BiThrNode p){
        if(p!=null){
            InThreading(p.getLchild());
            if(p.getLchild()==null){
                p.setLTag("Thread");
                p.setLchild(pre);
            }
            if(pre.getRchild()==null){
                pre.setRTag("Thread");
                pre.setRchild(p);
            }
            pre=p;
            InThreading(p.getRchild());
        }
    }
    
    public static void InOrderTraverse_Thr(BiThrNode T){
        BiThrNode p;
        p = T.getLchild();   //p指向根节点
        while(p != T){
            while(p.getLTag() == null){
                p = p.getLchild();
            }
            System.out.print(p.getData() + " ");
            while(p.getRTag()=="Thread"){
                p = p.getRchild();
                System.out.println(p.getData() + " ");
            }
            p = p.getRchild();
        }
    }
    public static void main(String[] args){
        BiThrNode ba = new BiThrNode();
        BiThrNode bb = new BiThrNode();
        BiThrNode bc = new BiThrNode();
        BiThrNode bd = new BiThrNode();
        BiThrNode be = new BiThrNode();
        BiThrNode bf = new BiThrNode();
        BiThrNode head = new BiThrNode();
        ba.setLchild(bb);
        ba.setRchild(bc);
        bb.setLchild(bd);
        bb.setRchild(be);
        bc.setRchild(bf);
        head.setLchild(ba);
        ba.setData("A");
        bb.setData("B");
        bc.setData("C");
        bd.setData("D");
        be.setData("E");
        bf.setData("F");
        BiThrNode p = ba;
        pre = p;
        InThreading(p);
          p = head;
        InOrderTraverse_Thr(p);
    }
}