1339. 分裂二叉树的最大乘积
链接：
1339. 分裂二叉树的最大乘积
题解：
/*** 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:int maxProduct(TreeNode* root) {if (!root) {return 0;}int sum = 0;dfs(root, sum);long long result = 0;dfs2(root, sum, result); int mod = 1000000007;return result%mod;}
private:void dfs(TreeNode* root, int& sum) {if (!root) {return;}sum += root->val;dfs(root->left, sum);dfs(root->right, sum);}int dfs2(TreeNode* root, int sum, long long& result) {if (!root) {return 0;}long long cur = dfs2(root->left, sum, result) + dfs2(root->right, sum, result) + root->val;long long tmp_result = (sum-cur)*cur;if (tmp_result > result) {result = tmp_result;}return cur;}
};