二叉树翻转

给定一棵二叉树的根节点 root，请左右翻转这棵二叉树，并返回其根节点。

示例 1：

输入：root = [5,7,9,8,3,2,4]
输出：[5,9,7,4,2,3,8]

提示：

• 树中节点数目范围在 [0, 100] 内
• -100 <= Node.val <= 100

思路：

将二叉树看成一个只有左右子树的最小二叉树，那么翻转这个二叉树就是将左右子树对换；然后再分别将左右子树当成一个完整的二叉树重复上述步骤

package leetcode.editor.cn;

public class ErChaShuDeJingXiangLcof{
    public static void main(String[] args) {
        Solution solution = new ErChaShuDeJingXiangLcof().new Solution();

    }

//leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public TreeNode mirrorTree(TreeNode root) {
        if(root==null) return root;
        TreeNode left = root.left;
        TreeNode right = root.right;
        root.left =right;
        root.right = left;
        mirrorTree(root.left);
        mirrorTree(root.right);
        return root;

    }
}
//leetcode submit region end(Prohibit modification and deletion)


}