二叉树相关知识总结（三）

package com.example.demo.dataStructure.binaryTree;

public class BinarySortTree {
    
    public static void main(String[] args) {
        BinarySortTree bst = new BinarySortTree();
        int array[] = {9,8,7,6,5,4,3,2,1};
        TreeNode tree = bst.createBinarySortTree(array);
        bst.inOrderTraversal(tree);
    }
    
    public TreeNode root;
    
    public TreeNode createBinarySortTree(int[] num) {
        TreeNode tree = null;
        for(int i=0;i<num.length;i++) {
            tree = addNode(new TreeNode(num[i])); // 思考：创建一颗树的时候，根节点的选取标准，创建之后树的高度
        }
        return tree;
    }
    
    /**
     * 中根遍历
     */
    public void inOrderTraversal(TreeNode tree) {
        if (null == tree) {
            return;
        }
        inOrderTraversal(tree.getLeftChild());
        System.out.print(tree.getData());
        inOrderTraversal(tree.getRightChild());
    }
    
    /**
     * 添加节点
     * @param node
     */
    public TreeNode addNode(TreeNode node) {
        if (root == null) {
            root = node;
            return root;
        }
        TreeNode current = root;
        while(true) {
            if(node.getData() <= current.getData()) { // 插入节点的值小于等于当前节点的值，放左子树
                if(current.getLeftChild() == null) {
                    current.setLeftChild(node);
                    return root;
                }
                current = current.getLeftChild();
            } else { // 插入节点的值小于等于当前节点的值，放左子树
                if(current.getRightChild() == null) {
                    current.setRightChild(node);
                    return root;
                }
                current = current.getRightChild();
            }
        }
    }
    
    class TreeNode {
        private TreeNode leftChild; // 左孩子
        private TreeNode rightChild; // 右孩子
        private int data; // 数据部分
        
        public TreeNode() {
            super();
        }
        
        // 初始化节点
        public TreeNode(TreeNode leftChild, TreeNode rightChild, int data) {
            super();
            this.leftChild = leftChild;
            this.rightChild = rightChild;
            this.data = data;
        }
        
        // 初始化数据域
        public TreeNode(int data) {
            this(null, null, data);
        }

        public TreeNode getLeftChild() {
            return leftChild;
        }

        public void setLeftChild(TreeNode leftChild) {
            this.leftChild = leftChild;
        }

        public TreeNode getRightChild() {
            return rightChild;
        }

        public void setRightChild(TreeNode rightChild) {
            this.rightChild = rightChild;
        }

        public int getData() {
            return data;
        }

        public void setData(int data) {
            this.data = data;
        }
    }
}