请大家帮忙分析分析?
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public void flatten(TreeNode root) {
if (root == null) {
return;
}
if (root.left != null) {
flatten(root.left);
}
if (root.right != null) {
flatten(root.right);
}
TreeNode tmp = root.right;
root.right = root.left;
root.left = null;
while (root != null && root.right != null) {
root = root.right;
}
root.right = tmp;
}
}