二叉树的镜像

浅浅的花香味﹌ 2022-05-24 22:36 240阅读 0赞

![这里写图片描述][70]

class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;
    
        public TreeNode(int val) {
            this.val = val;
    
        }
    
    }
    
    public class Solution {
    
            //方法二:精简递归方法
          public void Mirror2(TreeNode root) {
            TreeNode tmp = null;
            if (root != null)
                {
                tmp = root.left;
                root.left = root.right;
                root.right = tmp;
                if (root.left != null)
                    Mirror2(root.left);
                if (root.right != null)
                    Mirror2(root.right);
            }
        }
    
           //方法一:一般递归方法
        public void Mirror(TreeNode root) {
            if(root==null||(root.left==null&&root.right==null))
            {
                return;
            }
           Switch(root);
    
        }
        public void Switch(TreeNode root){
    
            if(root.left!=null&&root.right!=null){
    
              TreeNode temp=root.left;
              root.left=root.right;
              root.right=temp;
            }else if(root.left==null)
            {
                root.left=root.right;
                root.right=null;
    
            }else if(root.right==null)
            {
                root.right=root.left;
                root.left=null;
            }else{
                return;
            }
            if(root.left!=null)
            {
                 Switch(root.left);
            }
    
            if(root.right!=null)
            {
                Switch(root.right);
            }
    
        }
        //二叉树的中序遍历
        public void inOrder(TreeNode head){
    
             if(head!=null){
                 inOrder(head.left);
                 visit(head);
                 inOrder(head.right);
             }
        }
        public void visit(TreeNode node){
    
             System.out.print(node.val+" ");
        }
        public static void main(String[]args){
           // System.out.println("Hello");
            Solution s=new Solution();
            TreeNode head=new TreeNode(8);
            head.left=new TreeNode(6);
            head.right=new TreeNode(10);
            head.left.left=new TreeNode(5);
            head.left.right=new TreeNode(7);
            head.right.left=new TreeNode(9);
            head.right.right=new TreeNode(11);
    
            TreeNode head2=new TreeNode(8);
            head2.left=new TreeNode(7);
            head2.left.left=new TreeNode(6);
            head2.left.left.left=new TreeNode(5);
            head2.left.left.left.left=new TreeNode(4);
    
            s.inOrder(head2);
            System.out.println();
            s.Mirror(head2);
            s.inOrder(head2);
    
        }
    }

![这里写图片描述][70 1]

[70]: /images/20220525/0774c83ce9fb456396b7888214f13938.png
[70 1]: /images/20220525/35acbe6f60584f01be1ac4b961632559.png