LeetCode 之 Invert Binary Tree

LeetCode : Invert Binary Tree 
题目原意：反转一棵二叉树，即交换树的每一个左右节点； 

代码如下（leetCode 测得运行时间为0ms）：

struct TreeNode *invertTree(struct TreeNode *root)
{
	struct TreeNode *tmp = NULL;

	if (root == NULL)
	{
		return NULL;
	}

	//!< 先交换左右节点，再分别对左右节点递归
	tmp = root->right;
	root->right = root->left;
	root->left  = tmp;

	if (root->right)
	{
		invertTree(root->right);
	}

	if (root->left)
	{
		invertTree(root->left);
	}

	return root;
}