- 对于递归的写法除了大写的服字，无话可说
- 由于是修剪二叉树，所以会有明确的方向性
- 当某一结点小于最小值，说明其左子树全部要修剪掉
- 当某一结点大于最大值，说明其右子树全部要修剪掉
#include <iostream>struct TreeNode {int val;TreeNode* left;TreeNode* right;TreeNode(): val(0), left(nullptr), right(nullptr) {}TreeNode(int v): val(v), left(nullptr), right(nullptr) {}TreeNode(int v, TreeNode* l, TreeNode* r): val(v), left(l), right(r) {}
};class Solution {
public:TreeNode* trimBST(TreeNode* root, int low, int high) {if (root == nullptr)return nullptr;else if (root->val < low)return trimBST(root->right, low, high);else if (root->val > high)return trimBST(root->left, low, high);root->left = trimBST(root->left, low, high);root->right = trimBST(root->right, low, high);return root;}
};
int main()
{Solution s;return 0;
}
