二叉树中的最大子树总和，以使子树也是C ++中的BST
在本教程中，我们将讨论在二进制树中找到最大子树总和的程序，以使子树也是BST。
为此，我们将提供一个二叉树。我们的任务是打印子树的总和，该子树也是二叉搜索树。
示例
#include <bits/stdc++.h>
using namespace std;
//创建二叉树节点
struct Node {
struct Node* left; struct Node* right; int data;
Node(int data) {
this->data = data;
this->left = NULL;
this->right = NULL;
}
};
struct Info {
int max;
int min;
bool isBST;
int sum;
int currmax;
};
Info MaxSumBSTUtil(struct Node* root, int& maxsum) {
if (root == NULL) return { INT_MIN, INT_MAX, true, 0, 0 };
if (root->left == NULL && root->right == NULL) {
maxsum = max(maxsum, root->data);
return { root->data, root->data, true, root->data, maxsum };
}
Info L = MaxSumBSTUtil(root->left, maxsum);
Info R = MaxSumBSTUtil(root->right, maxsum);
Info BST;
if (L.isBST && R.isBST && L.max < root->data && R.min > root->data) {
BST.max = max(root->data, max(L.max, R.max));
BST.min = min(root->data, min(L.min, R.min));
maxsum = max(maxsum, R.sum + root->data + L.sum);
BST.sum = R.sum + root->data + L.sum;
BST.currmax = maxsum;
BST.isBST = true;
return BST;
}
BST.isBST = false;
BST.currmax = maxsum;
BST.sum = R.sum + root->data + L.sum;
return BST;
}
int MaxSumBST(struct Node* root) {
int maxsum = INT_MIN;
return MaxSumBSTUtil(root, maxsum).currmax;
}
int main() {
struct Node* root = new Node(5);
root->left = new Node(14);
root->right = new Node(3);
root->left->left = new Node(6);
root->right->right = new Node(7);
root->left->left->left = new Node(9);
root->left->left->right = new Node(1);
cout << MaxSumBST(root);
return 0;
}输出结果
10