二叉树的创建Java实现

悠悠 2022-03-25 10:46 173阅读 0赞

**关键词：**二叉树结点类、二叉树类

1.二叉树结点类的设计

class BiTreeNode {
    	int data;//设数据域非负
    	BiTreeNode leftChild;
    	BiTreeNode rightChild;
    	
    	public BiTreeNode(){
    		data = -1;//负数表示空
    		leftChild = rightChild = null;
    	}
    	public BiTreeNode(int d, BiTreeNode left, BiTreeNode right){
    		data = d;
    		leftChild = left;
    		rightChild = right;
    	}
    	public int getData(){
    		return data;
    	}
    	public void setData(int d){
    		data = d;
    	}
    	public BiTreeNode getLeftChild(){
    		return leftChild; 
    	}
    	public BiTreeNode getRightChild(){
    		return rightChild; 
    	}
    	public void setLeftChild(BiTreeNode left){
    		leftChild = left;
    	}
    	public void setLeftChild(BiTreeNode right){
    		rightChild = right;
    	}
    }

2.二叉树类的设计

class BinaryTree {
    	BiTreeNode root;//根结点
    	
    	public BinaryTree(){
    		root = null;
    	}
    	public BiTreeNode getRoot(){
    		return root;
    	}
    	public boolean isEmpty(){
    		return root == null;
    	}
    	//获取当前结点的父结点
    	public BiTreeNode getParent(BiTreeNode current){
    		return parent(root, current);
    	}
    	public BiTreeNode getParent(BiTreeNode start, BiTreeNode current){
    		if(start==null) return null;
    		if(start.leftChild==current || start.rightChild==current)
    			return start;
    		BiTreeNode p;
    		if(p=parent(start.leftChild, current)!=null)
    			return p;
    		else
    			return parent(start.rightChild, current);
    	}
    	public BiTreeNode findNode(int d){}
    	public BiTreeNode insertNode(int d){}
    	public BiTreeNode removeNode(){int d}
    	//二叉树的先序遍历
    	private void preOrder(){//从根结点开始
    		preOrder ( root );
    	}
    	private void preOrder(BiTreeNode current){//从某个结点开始
    		if (current != null){
    			System.out.print(current.data);
    			preOrder(current.leftChild );
    			preOrder(current.rightChild );
    		}
    	}
    	//二叉树的中序遍历
    	private void inOrder(){//从根结点开始
    		inOrder ( root );
    	}
    	private void inOrder(BiTreeNode current){//从某个结点开始
    		if (current != null){
    			inOrder(current.leftChild );
    			System.out.print(current.data);
    			inOrder(current.rightChild );
    		}
    	}
    	//二叉树的后序遍历
    	private void postOrder(){//从根结点开始
    		postOrder ( root );
    	}
    	private void postOrder(BiTreeNode current){//从某个结点开始
    		if (current != null){
    			postOrder(current.leftChild );
    			postOrder(current.rightChild );
    			System.out.print(current.data);
    		}
    	}
    	//获取二叉树的结点个数
    	private int getSize(){//获取整棵二叉树的结点数
    		return getSize(root);
    	}
    	private int getSize(BiTreeNode current){//获取某个结点构成的子树的结点总数
    		if (current == null) return 0;
    		else
    			return 1+getSize(current.leftChild)+getSize(current.rightChild);
    	}
    	//获取二叉树的高度
    	public int getHeight(){//整棵树
    		return getHeight(root);
    	}
    	public int getHeight(BiTreeNode current){//某结点构成的子树
    		if (current == null) return 0;
    		else
    			return 1+max(getHeight(current.leftChild)+getHeight(current.rightChild);
    		//max(int a, int b)是Math库中的函数，取二者中最大的
    	}
    }

上面二叉树的遍历是以递归的形式实现的，还有非递归的方式实现前中后三种遍历