记住:二叉搜索树的中序遍历就是排序后的节点顺序!(做着做着就忘了这个很重要的点)

public class Solution {
    private TreeNode list = null, listHead = null;

    public TreeNode Convert(TreeNode pRootOfTree) {
        if (pRootOfTree == null) {
            return null;
        }
        Convert(pRootOfTree.left);
        if (list == null) {
            list = pRootOfTree;
            listHead = list;
        } else {
            list.right = pRootOfTree;
            pRootOfTree.left = list;
            list = pRootOfTree;
        }
        Convert(pRootOfTree.right);
        return listHead;
    }
}