【树】面试题27. 二叉树的镜像

题目：

 

 

 

解法：

本题与主站 226 题相同：https://leetcode-cn.com/problems/invert-binary-tree/

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* mirrorTree(TreeNode* root) 
    {
        if (NULL == root) 
        {
            return root;
        }
        TreeNode *right = mirrorTree(root->right);
        TreeNode *left = mirrorTree(root->left);
        root->left = right;
        root->right = left;
        return root;

    }
};