# Leetcode 226. Invert Binary Tree
###### tags: `Leetcode`

題目
Given the root of a binary tree, invert the tree, and return its root.

解法

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */


struct TreeNode* invertTree(struct TreeNode* root){
    當下節點若是NULL，就直接return
    if(root == NULL)
        return NULL;
    //若不是NULL，就把左右節點做交換
    struct TreeNode* temp;
    temp = root->left;
    root->left = root->right;
    root->right = temp;
    //交換完後，在換成做又節點下面進行交換
    invertTree(root->left);
    invertTree(root->right);
    return root;
}