10分钟二叉树的非递归排序完成

import java.util.Stack;public class test_04_23 {//二叉树的三种遍历static class TreeNode{int data;TreeNode left;TreeNode right;public TreeNode(int data){this.data = data;}}//先序遍历public static void test1(TreeNode root){Stack<TreeNode> stack = new Stack<>();stack.push(root);while (!stack.isEmpty()){TreeNode node = stack.pop();System.out.println(node.data);if (node.right!=null){stack.push(node.right);}if (node.left!=null){stack.push(node.left);}}}//中序遍历public static void test2(TreeNode root){Stack<TreeNode> stack = new Stack<>();TreeNode p = root;while (p!=null||!stack.isEmpty()){if (p!=null){stack.push(p);p=p.left;}else{TreeNode node = stack.pop();System.out.println(node.data);if (node.right!=null){p=node.right;}}}}//后序遍历public static void test3(TreeNode root){Stack<TreeNode> stack = new Stack<>();TreeNode p = root;TreeNode r = null;while (p!=null||!stack.isEmpty()){if (p!=null){stack.push(p);p=p.left;}else{TreeNode pNode = stack.peek();if (pNode.right!=null&&pNode.right!=r){p=pNode.right;}else{TreeNode node = stack.pop();System.out.println(node.data);r = pNode;}}}}//    1//  2   3// 4 5 6 7public static void main(String[] args) {TreeNode root = new TreeNode(1);root.left=new TreeNode(2);root.right=new TreeNode(3);root.left.left=new TreeNode(4);root.left.right=new TreeNode(5);root.right.left=new TreeNode(6);root.right.right=new TreeNode(7);test3(root);}
}