思路:
用一个递归思路,很简单
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public void flatten(TreeNode root) {
if(root==null)
{
return;
}
flatten(root.left);
TreeNode right=root.right;
if(root.left!=null)
{
TreeNode temp=root.left;
while(temp.right!=null)
{
temp=temp.right;
}
root.right=root.left;
temp.right=right;
}
root.left=null;
flatten(right);
}
}