算法——二叉树

package com.demo.calculate;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

import com.demo.calculate.bean.BinaryTree;
import com.demo.calculate.bean.TreeNode;

public class TreeActivit extends Activity {
    private  BinaryTree binaryTree;
    @Override
    protected void onCreate( Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tree);
        //创建一棵空树
        binaryTree = new BinaryTree();
        TreeNode root = new TreeNode(1);
        binaryTree.setRoot(root);
        //根节点的左节点
        TreeNode leftNode = new TreeNode(2);
        leftNode.setNodeLeft(new TreeNode(4));
        leftNode.setNodeRight(new TreeNode(5));
        //根节点的右节点
        TreeNode rightNode = new TreeNode(3);
        rightNode.setNodeLeft(new TreeNode(6));
        rightNode.setNodeRight(new TreeNode(7));
        root.setNodeLeft(leftNode);
        root.setNodeRight(rightNode);
        findViewById(R.id.btn_frontShow).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //前序遍历
                frontShow();
            }
        });
        findViewById(R.id.btn_midShow).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //中序遍历
                midShow();
            }
        });
        findViewById(R.id.btn_afterShow).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //后序遍历
                afterShow();
            }
        });
        findViewById(R.id.btn_frontSearch).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //前序查找
                TreeNode result = frontSearch(5);
                Log.i("tag",result.getValue()+"=============");
            }
        });
        findViewById(R.id.btn_deleteNode).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //删除节点
                deleteNode(7);
                frontShow();
            }
        });
    }
    private void deleteNode(int i) {
        binaryTree.deleteNode(i);
    }
    //前序查找
    private TreeNode frontSearch(int i) {
        return binaryTree.frontSearch(i);
    }
    private void afterShow() {
        binaryTree.afterShow();
    }
    private void midShow() {
        binaryTree.midShow();
    }
    //前序遍历
    private void frontShow() {
        binaryTree.frontShow();
    }
}

package com.demo.calculate.bean;

public class BinaryTree {
    private int value;
    private TreeNode root;
    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public TreeNode getRoot() {
        return root;
    }

    public void setRoot(TreeNode root) {
        this.root = root;
    }

    public void frontShow() {
        if (root!=null){
            root.frontShow();
        }
    }

    public void midShow() {
        if (root!=null){
            root.midShow();
        }

    }

    public void afterShow() {
        if (root!=null){
            root.afterShow();
        }
    }

    public TreeNode frontSearch(int i) {
        if (root!=null){
            return root.frontSearch(i);
        }
        return  null;
    }

    public void deleteNode(int i) {
        if (root!=null){
            root.deleteNode(i);
        }
    }
}

package com.demo.calculate.bean;

import android.util.Log;

public class TreeNode {
    private int value;
    private TreeNode nodeLeft;
    private TreeNode nodeRight;
    public void setNodeLeft(TreeNode nodeLeft) {
        this.nodeLeft = nodeLeft;
    }
    public void setNodeRight(TreeNode nodeRight) {
        this.nodeRight = nodeRight;
    }
    public TreeNode(int value) {
        this.value = value;
    }
    public void frontShow() {
        Log.i("tag",value+"");
        if (nodeLeft!=null){
            nodeLeft.frontShow();
        }
        if (nodeRight!=null){
            nodeRight.frontShow();
        }
    }
    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public void midShow() {
        if (nodeLeft!=null){
            nodeLeft.midShow();
        }
        Log.i("tag",value+"");
        if (nodeRight!=null){
            nodeRight.midShow();
        }
    }

    public void afterShow() {
        if (nodeLeft!=null){
            nodeLeft.afterShow();
        }
        if (nodeRight!=null){
            nodeRight.afterShow();
        }
        Log.i("tag",value+"");
    }
    //前序查找
    public TreeNode frontSearch(int i) {
        TreeNode target=null;
        if (this.value ==i){
            return this;
        }else{
            if (nodeLeft!=null){
                target = nodeLeft.frontSearch(i);
            }
            if (target!=null){
                return target;
            }
            if (nodeRight!=null){
                target = nodeRight.frontSearch(i);
            }
        }
        return target;
    }

    public void deleteNode(int i) {
        TreeNode parent = this;
        if (this.value==i){
            parent = null;
        }
        //判断左儿子
        if (parent!=null && parent.nodeLeft!=null && parent.nodeLeft.value==i){
            parent.nodeLeft = null;
            return;
        }
        //判断右儿子
        if (parent!=null && parent.nodeRight!=null && parent.nodeRight.value==i){
            parent.nodeRight = null;
            return;
        }
        //递归删除左面的儿子
        parent = nodeLeft;
        if (parent!=null){
            parent.deleteNode(i);
        }
        //递归删除右面的儿子
        parent = nodeRight;
        if (parent!=null){
            parent.deleteNode(i);
        }
    }
}