LeetCode 508. 出现次数最多的子树元素和
原题链接
中等
/**
* 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 {
public:
unordered_map<int, int> record;
vector<int> result;
int maxc = 0;
vector<int> findFrequentTreeSum(TreeNode* root) {
dfs(root);
return result;
}
int dfs(TreeNode* root) {
if(!root) return 0;
int sum = root->val + dfs(root->left) + dfs(root->right);
record[sum] ++;
if(record[sum] > maxc) {
maxc = record[sum];
result = {sum};
} else if(record[sum] == maxc) {
result.push_back(sum);
}
return sum;
}
};