[LeetCode]226. Invert Binary Tree(反转二叉树)

226. Invert Binary Tree

4
/   \
2     7
/ \   / \
1   3 6   9

4
/   \
7     2
/ \   / \
9   6 3   1

C++

/**
* 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* invertTree(TreeNode* root) {

if (root == NULL)
return NULL;
TreeNode* temp = root->left;
root->left = root->right;
root->right = temp;

invertTree(root->left);
invertTree(root->right);

return root;
}
};