java实现二叉搜索树转双向链表

/** * 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。 *  * @author pomay * */class Solution_treetolist{public TreeNode Convert(TreeNode pRootOfTree){TreeNode lastNodeOfList = null;// LastNodeOfList指向已经转换好的链表的最后一个结点// 返回头结点TreeNode headNodeOfList = ConvertNode(pRootOfTree, lastNodeOfList);// 一直倒退到头结点while (headNodeOfList != null && headNodeOfList.left != null)headNodeOfList = headNodeOfList.left;return headNodeOfList;}// 把二叉树转换成链表,获得链表最后结点（即最大结点）TreeNode ConvertNode(TreeNode pNode, TreeNode LastNodeOfList){if (pNode == null)return null;TreeNode current = pNode;if (current.left != null)// 把左子树转成链表LastNodeOfList = ConvertNode(current.left, LastNodeOfList);// 当前结点的左边就是左子树构成的链表的最后一个结点current.left = LastNodeOfList;if (LastNodeOfList != null)// 把转换好的链表后面连接当前结点LastNodeOfList.right = current;// 此时根转换好的链表最后一个结点就是当前结点LastNodeOfList = current;// 同理 把右子树转成链表if (current.right != null)LastNodeOfList = ConvertNode(current.right, LastNodeOfList);return LastNodeOfList;}public static void main(String[] args){TreeNode pRootOfTree = new TreeNode(10);pRootOfTree.left = new TreeNode(6);pRootOfTree.right = new TreeNode(14);pRootOfTree.left.left = new TreeNode(4);pRootOfTree.left.right = new TreeNode(8);pRootOfTree.right.left = new TreeNode(12);pRootOfTree.right.right = new TreeNode(16);Solution_treetolist treetolist = new Solution_treetolist();TreeNode result = treetolist.Convert(pRootOfTree);System.out.print(result.val + " " + result.right.val + " " + result.right.right.val + " "+ result.right.right.right.val + " " + result.right.right.right.right.val + " "+ result.right.right.right.right.right.val + " " + result.right.right.right.right.right.right.val);}}