算法11：LeetCode_对称二叉树

题目： 给你一个二叉树的根节点 root ， 检查它是否轴对称。

下面给了2个例子：

 

 

 

 

package code.code_03;

/**
 * 力扣 https://leetcode.cn/problems/symmetric-tree/
 * 对称二叉树，又称镜面树
 *
 * 给你一个二叉树的根节点 root ， 检查它是否轴对称。
 * 输入 root = [1,2,2,3,4,4,3]  输出：true
 * 输入 root = [1,2,2,null,3,null,3] false
 */
public class Code03_MirrioTree {

    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode() {}
        TreeNode(int val) { this.val = val; }
        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }

    public boolean isMirrioNode(TreeNode h1, TreeNode h2)
    {
        if (h1 == null && h2 == null) {
            return true;
        }

        if ((h1 == null && h2 != null)
                || (h1 != null && h2 == null)
                || h1.val != h2.val){
            return false;
        }

        /*if ((h1 == null ^ h2 == null) || h1.val != h2.val) {
            return false;
        }*/

        return isMirrioNode(h1.left, h2.right) && isMirrioNode(h1.right, h2.left);
    }

    public boolean isSymmetric(TreeNode root)
    {
        if (root == null) {
            return false;
        }
        return isMirrioNode(root.left, root.right);
    }


    public static void main(String[] args) {

    }
}