Sword finger offer 27 Image of binary tree

Original link ： The finger of the sword Offer 27. Image of binary tree

 

solution:

class Solution {
public:
    TreeNode* mirrorTree(TreeNode* root) {
        if(root == NULL) return NULL;
        swap(root->left,root->right);
        mirrorTree(root->left);
        mirrorTree(root->right);
        return root;
    }
};