LeetCode501 二叉搜索树中的众数

前言

题目： 501. 二叉搜索树中的众数
文档： 代码随想录——二叉搜索树中的众数
编程语言： C++
解题状态： 不会…

思路

利用二叉搜索树性质的同时再加上双指针法。

代码

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
private:int maxCount = 0;int count = 0;TreeNode* pre = NULL;vector<int> result;void searchBST(TreeNode* cur) {if (!cur) return;searchBST(root -> left);if (pre == NULL) {count = 1;} else if (pre -> val == cur -> val) {count++;} else {count = 1;}pre = cur;if (count == maxCount) {result.push_back(cur ->val);}if (count > maxCount) {maxCount = count;result.clear();result.push_back(cur -> val);}searchBST(root -> right);return;}public:vector<int> findMode(TreeNode* root) {count = 0;maxCount = 0;pre = NULL;result.clear();searchBST(root);return result;}
};