二叉树反转简化

Author: xbox1994

MD/算法-二叉树-二叉树反转.md

@@ -16,82 +16,17 @@
 ```
 
 ```java
-import java.util.LinkedList;
-
-class TreeNode {
-    public TreeNode left;
-    public TreeNode right;
-    public int value;
-
-    public TreeNode(int value) {
-        this.value = value;
-    }
-
-    public TreeNode invertNode(TreeNode root) {
-        if (root == null) {
+class Solution {
+    public TreeNode invertTree(TreeNode root) {
+        if(root == null){
             return null;
         }
+        invertTree(root.left);
+        invertTree(root.right);
         TreeNode temp = root.left;
-        root.left = invertNode(root.right);
-        root.right = invertNode(temp);
+        root.left = root.right;
+        root.right = temp;
         return root;
     }
-//    另一种写法
-//    public TreeNode invertNode(TreeNode root) {
-//        if (root == null) {
-//            return null;
-//        }
-//        TreeNode temp = root.left;
-//        root.left = root.right;
-//        root.right = temp;
-//        invertNode(root.left);
-//        invertNode(root.right);
-//        return root;
-//    }
-
-    // 该方法是按二叉树每层从左往右的顺序打印结点，不属于本题考察的范围，但也属于面试题目中会考察的问题
-    public void printTreeNode() {
-        LinkedList<TreeNode> queue = new LinkedList<>();
-        queue.add(this);
-
-        TreeNode currentLineRightestNode = new TreeNode(this.value); // 直接使用this会将root的value改变，所以需要clone一个相同值的对象
-        TreeNode nextLineRightestNode = null;
-
-        while (!queue.isEmpty()) {
-            TreeNode currentNode = queue.poll();
-
-            if (currentNode.left != null) {
-                queue.add(currentNode.left);
-                nextLineRightestNode = currentNode.left;
-            }
-            if (currentNode.right != null) {
-                queue.add(currentNode.right);
-                nextLineRightestNode = currentNode.right;
-            }
-
-            System.out.print(currentNode.value);
-
-            if (currentNode.value == currentLineRightestNode.value) {
-                System.out.println();
-                currentLineRightestNode.value = nextLineRightestNode.value;
-            }
-        }
-    }
-}
-
-public class ReverseBinaryTree {
-    public static void main(String[] args) {
-        TreeNode root = new TreeNode(4);
-        root.left = new TreeNode(2);
-        root.right = new TreeNode(7);
-        root.left.left = new TreeNode(1);
-        root.left.right = new TreeNode(3);
-        root.right.left = new TreeNode(6);
-        root.right.right = new TreeNode(9);
-        root.printTreeNode();
-        System.out.println("-------");
-        root.invertNode(root);
-        root.printTreeNode();
-    }
 }
 ```