数据结构与算法学习Java版-二叉树

遍历实现代码：

package 数据结构;

public class BinaryTreeDemo {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		//先创建二叉树
		BinaryTree binaryTree=new BinaryTree();
		//创建节点
		HeroNode1 root=new HeroNode1(1, "宋江");
		HeroNode1 node2=new HeroNode1(2, "吴用");
		HeroNode1 node3=new HeroNode1(3, "李逵");
		HeroNode1 node4=new HeroNode1(4, "鲁智深");
		//手动创建二叉树
		binaryTree.setRoot(root);
		root.setLeft(node2);
		root.setRight(node3);
		node3.setRight(node4);
		
		//遍历二叉树
		//1、前序遍历
		System.out.println("前序遍历");
		binaryTree.preOrder();
		//2、中序遍历
		System.out.println("中序遍历");
		binaryTree.infixOrder();
		//3、后序遍历
		System.out.println("后序遍历");
		binaryTree.postOrder();
	}

}
//定义二叉树
class BinaryTree{
	private HeroNode1 root;
	public void setRoot(HeroNode1 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");
		}
		
	}
	public void infixOrder() {
		if(this.root!=null) {
			this.root.infixOrder();
		}else {
			System.out.println("为空");
		}
	}
	public void postOrder() {
		if(this.root!=null) {
			this.root.postOrder();
		}else {
			System.out.println("为空");
		}
	}
}
class HeroNode1{
	private int no;
	private String name;
	private HeroNode1 left;//默认为null
	private HeroNode1 right;
	public HeroNode1(int no,String name) {
		this.no=no;
		this.name=name;
	}
	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 HeroNode1 getLeft() {
		return left;
	}
	public void setLeft(HeroNode1 left) {
		this.left = left;
	}
	public HeroNode1 getRight() {
		return right;
	}
	public void setRight(HeroNode1 right) {
		this.right = right;
	}
	//重写toString
	@Override
	public String toString() {
		return "Heronode [no=" + no + ", name=" + name + "]";
	}
	//前序遍历方法
	public void preOrder() {
		//先输出父节点
		System.out.println(this);
		//递归向左子树前序遍历
		if(this.left!=null) {
			this.left.preOrder();
		}
		//
		if(this.right!=null) {
			this.right.preOrder();
		}
	}
	//中序遍历方法
	public void infixOrder() {
		//递归向左子树遍历
		if(this.left!=null) {
			this.left.infixOrder();
		}
		//输出父节点
		System.out.println(this);
		//
		if(this.right!=null) {
			this.right.infixOrder();
		}
	}
	public void postOrder() {
		if(this.left!=null) {
			this.left.postOrder();
		}
		if(this.right!=null) {
			this.right.postOrder();
		}
		//输出父节点
		System.out.println(this);
	}
}

运行结果：

前序遍历
Heronode [no=1, name=宋江]
Heronode [no=2, name=吴用]
Heronode [no=3, name=李逵]
Heronode [no=4, name=鲁智深]
中序遍历
Heronode [no=2, name=吴用]
Heronode [no=1, name=宋江]
Heronode [no=3, name=李逵]
Heronode [no=4, name=鲁智深]
后序遍历
Heronode [no=2, name=吴用]
Heronode [no=4, name=鲁智深]
Heronode [no=3, name=李逵]
Heronode [no=1, name=宋江]

前序查找代码实现

package 数据结构;

public class BinaryTreeDemo {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		//先创建二叉树
		BinaryTree binaryTree=new BinaryTree();
		//创建节点
		HeroNode1 root=new HeroNode1(1, "宋江");
		HeroNode1 node2=new HeroNode1(2, "吴用");
		HeroNode1 node3=new HeroNode1(3, "李逵");
		HeroNode1 node4=new HeroNode1(4, "鲁智深");
		//手动创建二叉树
		binaryTree.setRoot(root);
		root.setLeft(node2);
		root.setRight(node3);
		node3.setRight(node4);
		
		//遍历二叉树
		//1、前序遍历
		System.out.println("前序遍历");
		binaryTree.preOrder();
		//2、中序遍历
		System.out.println("中序遍历");
		binaryTree.infixOrder();
		//3、后序遍历
		System.out.println("后序遍历");
		binaryTree.postOrder();
		
		//前序查找
		System.out.println("前序查找");
		HeroNode1 resNode=binaryTree.preOrderSearch(2);
		if(resNode!=null) {
			System.out.printf("no=%d,name=%s",resNode.getNo(),resNode.getName());
		}
	}

}
//定义二叉树
class BinaryTree{
	private HeroNode1 root;
	public void setRoot(HeroNode1 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");
		}
		
	}
	public void infixOrder() {
		if(this.root!=null) {
			this.root.infixOrder();
		}else {
			System.out.println("为空");
		}
	}
	public void postOrder() {
		if(this.root!=null) {
			this.root.postOrder();
		}else {
			System.out.println("为空");
		}
	}
	//前序查找
	public HeroNode1 preOrderSearch(int no) {
		if(root!=null) {
			return root.preOrderSearch(no);
		}else {
			return null;
		}
	}
}
class HeroNode1{
	private int no;
	private String name;
	private HeroNode1 left;//默认为null
	private HeroNode1 right;
	public HeroNode1(int no,String name) {
		this.no=no;
		this.name=name;
	}
	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 HeroNode1 getLeft() {
		return left;
	}
	public void setLeft(HeroNode1 left) {
		this.left = left;
	}
	public HeroNode1 getRight() {
		return right;
	}
	public void setRight(HeroNode1 right) {
		this.right = right;
	}
	//重写toString
	@Override
	public String toString() {
		return "Heronode [no=" + no + ", name=" + name + "]";
	}
	//前序遍历方法
	public void preOrder() {
		//先输出父节点
		System.out.println(this);
		//递归向左子树前序遍历
		if(this.left!=null) {
			this.left.preOrder();
		}
		//
		if(this.right!=null) {
			this.right.preOrder();
		}
	}
	//中序遍历方法
	public void infixOrder() {
		//递归向左子树遍历
		if(this.left!=null) {
			this.left.infixOrder();
		}
		//输出父节点
		System.out.println(this);
		//
		if(this.right!=null) {
			this.right.infixOrder();
		}
	}
	public void postOrder() {
		if(this.left!=null) {
			this.left.postOrder();
		}
		if(this.right!=null) {
			this.right.postOrder();
		}
		//输出父节点
		System.out.println(this);
	}
	//前序查找
	public HeroNode1 preOrderSearch(int no) {
		//比较当前节点，是则返回
		if(this.no==no) {
			return this;
		}
		//判断左子树是否为空，不为空则递归查找
		
		HeroNode1 resNode=null;//记录结果
		if(this.left!=null) {
			resNode=this.left.preOrderSearch(no);
		}
		if(resNode!=null) {
			return resNode;//找到返回
		}
		//未找到则看右子树
		if(this.right!=null) {
			resNode=this.right.preOrderSearch(no);
		}
		return resNode;//不管找未找到都返回
	}
}

package 数据结构;

public class BinaryTreeDemo {

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		//先创建二叉树
		BinaryTree binaryTree=new BinaryTree();
		//创建节点
		HeroNode1 root=new HeroNode1(1, "宋江");
		HeroNode1 node2=new HeroNode1(2, "吴用");
		HeroNode1 node3=new HeroNode1(3, "李逵");
		HeroNode1 node4=new HeroNode1(4, "鲁智深");
		//手动创建二叉树
		binaryTree.setRoot(root);
		root.setLeft(node2);
		root.setRight(node3);
		node3.setRight(node4);
		
		//遍历二叉树
		//1、前序遍历
		System.out.println("前序遍历");
		binaryTree.preOrder();
		//2、中序遍历
		System.out.println("中序遍历");
		binaryTree.infixOrder();
		//3、后序遍历
		System.out.println("后序遍历");
		binaryTree.postOrder();
		
		//前序查找
		System.out.println("前序查找");
		HeroNode1 resNode=binaryTree.preOrderSearch(2);
		if(resNode!=null) {
			System.out.printf("no=%d,name=%sn",resNode.getNo(),resNode.getName());
		}
		//删除节点
		System.out.println("删除节点");
		binaryTree.delNode(4);
		//再次查看
		binaryTree.preOrder();
	}

}
//定义二叉树
class BinaryTree{
	private HeroNode1 root;
	public void setRoot(HeroNode1 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");
		}
		
	}
	public void infixOrder() {
		if(this.root!=null) {
			this.root.infixOrder();
		}else {
			System.out.println("为空");
		}
	}
	public void postOrder() {
		if(this.root!=null) {
			this.root.postOrder();
		}else {
			System.out.println("为空");
		}
	}
	//前序查找
	public HeroNode1 preOrderSearch(int no) {
		if(root!=null) {
			return root.preOrderSearch(no);
		}else {
			return null;
		}
	}
	//删除节点
	public void delNode(int no) {
		if(root!=null) {
			if(root.getNo()==no) {
				root=null;
			}else {
				//递归删除
				root.delNode(no);
			}
		}else {
			System.out.println("为空");
		}
	}
}
class HeroNode1{
	private int no;
	private String name;
	private HeroNode1 left;//默认为null
	private HeroNode1 right;
	public HeroNode1(int no,String name) {
		this.no=no;
		this.name=name;
	}
	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 HeroNode1 getLeft() {
		return left;
	}
	public void setLeft(HeroNode1 left) {
		this.left = left;
	}
	public HeroNode1 getRight() {
		return right;
	}
	public void setRight(HeroNode1 right) {
		this.right = right;
	}
	//重写toString
	@Override
	public String toString() {
		return "Heronode [no=" + no + ", name=" + name + "]";
	}
	//前序遍历方法
	public void preOrder() {
		//先输出父节点
		System.out.println(this);
		//递归向左子树前序遍历
		if(this.left!=null) {
			this.left.preOrder();
		}
		//
		if(this.right!=null) {
			this.right.preOrder();
		}
	}
	//中序遍历方法
	public void infixOrder() {
		//递归向左子树遍历
		if(this.left!=null) {
			this.left.infixOrder();
		}
		//输出父节点
		System.out.println(this);
		//
		if(this.right!=null) {
			this.right.infixOrder();
		}
	}
	public void postOrder() {
		if(this.left!=null) {
			this.left.postOrder();
		}
		if(this.right!=null) {
			this.right.postOrder();
		}
		//输出父节点
		System.out.println(this);
	}
	//前序查找
	public HeroNode1 preOrderSearch(int no) {
		//比较当前节点，是则返回
		if(this.no==no) {
			return this;
		}
		//判断左子树是否为空，不为空则递归查找
		
		HeroNode1 resNode=null;//记录结果
		if(this.left!=null) {
			resNode=this.left.preOrderSearch(no);
		}
		if(resNode!=null) {
			return resNode;//找到返回
		}
		//未找到则看右子树
		if(this.right!=null) {
			resNode=this.right.preOrderSearch(no);
		}
		return resNode;//不管找未找到都返回
	}
	//删除节点
	public void delNode(int no) {
		if(this.left!=null&&this.left.no==no) {
			this.left=null;//重置为null即删除
			return;
		}
		if(this.right!=null&&this.right.no==no) {
			this.right=null;
			return;
		}
		//向左子树递归删除
		if(this.left!=null) {
			this.left.delNode(no);
		}
		if(this.right!=null) {
			this.right.delNode(no);
		}
	}
}