代码随想录算法训练营第二十天-二叉树-669. 修剪二叉搜索树

taoyong0012025-01-02 16:56

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

cpp 复制代码

#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;
}

汇总