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 );    }};