LeetCode (Flatten Binary Tree to Linked List)

Problem:

Given a binary tree, flatten it to a linked list in-place.

For example,
Given

         1        / \       2   5      / \   \     3   4   6

The flattened tree should look like:

   1    \     2      \       3        \         4          \           5            \             6

Solution:

/** * 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:    void flatten(TreeNode* root) {        if(root){            flatten(root->left);            flatten(root->right);            if(root->left){                TreeNode* right = root->right;                root->right = root->left;                root->left = NULL;                TreeNode* temp = root->right;                while(temp->right)                    temp = temp->right;                temp->right = right;            }        }       }};