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。
代码实现
class Solution {
public:
TreeNode* Convert(TreeNode* pRootOfTree)
{
if(pRootOfTree == nullptr) return nullptr;
TreeNode* pre = nullptr;
convertHelper(pRootOfTree, pre);
TreeNode* res = pRootOfTree;
while(res ->left)
res = res ->left;
return res;
}
void convertHelper(TreeNode* cur, TreeNode*& pre)
{
if(cur == nullptr) return;
convertHelper(cur ->left, pre);
cur ->left = pre;
if(pre) pre ->right = cur;
pre = cur;
convertHelper(cur ->right, pre);
}
};