leetcode-二叉搜索树与双向链表-89

题目要求

思路
1.观察给的用例，本质上是把数据按照中序遍历连接起来
2.将结点以中序遍历的方式插入到数组中，注意这里是vector
3.将数组中的数据连接起来

代码实现

/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
	vector<TreeNode*> res;
    TreeNode* Convert(TreeNode* pRootOfTree) {
        if (pRootOfTree == nullptr)
			return nullptr;
		midorder(pRootOfTree);
		for(int i = 0; i < res.size()-1; i++)
		{
			res[i]->right = res[i+1];
			res[i+1]->left = res[i];
		}
		return res[0];
    }

	void midorder(TreeNode* pRootOfTree)
	{
		if (pRootOfTree == nullptr)
			return;
		midorder(pRootOfTree->left);
		res.push_back(pRootOfTree);
		midorder(pRootOfTree->right);
	}
};

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