二叉搜索树与双向链表

题目描述

输入一棵二叉搜索树，将该二叉搜索树转换成一个排序的双向链表。要求不能创建任何新的结点，只能调整树中结点指针的指向。

 

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    private TreeNode head = null;
    private TreeNode pre = null;
    public TreeNode Convert(TreeNode pRootOfTree) {
        convert(pRootOfTree);
        return head;
    }
    public void convert(TreeNode node) {
        if(node == null)return;
        convert(node.left);
        node.left = pre;
        if(pre!=null){
            pre.right=node;
        }
        pre = node;
        if(head==null){
            head=node;
        }
        convert(node.right);
    }
}