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。

思路：
开局一张图。。。。其实主要就是按照中序遍历的过程，把树的节点递归连接成双向链表。

public class Convert {

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

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

    private TreeNode head ;
    private TreeNode realHead;
    public TreeNode Convert(TreeNode pRootOfTree){
        if(pRootOfTree == null){
            return null;
        }

        Convert(pRootOfTree.left);

        if(head ==null){
            head = pRootOfTree;
            realHead = pRootOfTree;
        }
        else {
            head.right = pRootOfTree;
            pRootOfTree.left = head;
            head = head.right;
        }

        Convert(pRootOfTree.right);

        return realHead;
    }
}