Java for LeetCode 114 Flatten Binary Tree to Linked List

標籤：

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
解題思路：
試圖通過排序後new TreeNode是無法通過的，這道題的意思是把現有的樹進行剪枝操作。JAVA實現如下：

    static public void flatten(TreeNode root) {    while(root!=null){            if(root.left!=null){                  TreeNode pre = root.left;                  while(pre.right!=null)                      pre = pre.right;                  pre.right = root.right;                  root.right = root.left;                  root.left = null;              }              root = root.right;          }     }

 

Java for LeetCode 114 Flatten Binary Tree to Linked List