Java for LeetCode 114 Flatten Binary Tree to Linked List

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
解题思路：
试图通过排序后new TreeNode是无法通过的，这道题的意思是把现有的树进行剪枝操作。JAVA实现如下：

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;
}
}