//判断一颗树是不是镜面树

package MirrorTree;
 
/**
 * @author 真他喵的学不动咯
 * @create 2022-08-14--14:41
 */
public class Mirror {   //判断一颗树是不是镜面树
    //https://leetcode.cn/problems/symmetric-tree/
 
    public static class TreeNode{
        public int val;
        public TreeNode left;
        public TreeNode right;
    }
    //用一个方法，传两棵树进去
    public static boolean isSymmetric(TreeNode root){
        return isMirror(root,root);
    }
    public static boolean isMirror(TreeNode h1,TreeNode h2){
        if (h1==null^h2==null){   //h1和h2有一个是空的，直接false
            return false;
        }
        if (h1==null&&h2==null){   //两个都是空的，直接true
            return true;
        }
        return h1.val==h2.val&&isMirror(h1.left,h2.right)&&isMirror(h1.right,h2.left);
        // 头结点不必镜面，必然相同       h1左=h2右               h1右=h2左
    }
}