LintCode - 175.翻转二叉树

翻转一棵二叉树

您在真实的面试中是否遇到过这个题？ 

Yes

样例

1         1
/ \       / \
2   3  => 3   2
/       \
4         4

/**
* Definition of TreeNode:
* class TreeNode {
* public:
* int val;
* TreeNode *left, *right;
* TreeNode(int val) {
* this->val = val;
* this->left = this->right = NULL;
* }
* }
*/
class Solution {
public:
/**
* @param root: a TreeNode, the root of the binary tree
* @return: nothing
*/
void invertBinaryTree(TreeNode *root) {
// write your code here
if( root == NULL ) return;

TreeNode* node = root->left;
root->left = root->right;
root->right = node;

invertBinaryTree( root->left );
invertBinaryTree( root->right );
}
};