#include
#include
using namespace std;
bool isBST(const int a[], int index, int minVal, int maxVal, int n) {
if (index >= n || a[index] == -1) {
return true;
}
if (a[index] <= minVal || a[index] >= maxVal) {
return false;
}
bool left = isBST(a, 2 * index + 1, minVal, a[index], n);
bool right = isBST(a, 2 * index + 2, a[index], maxVal, n);
return left && right;
}
int main() {
// 示例:用数组表示的二叉树
int arr[] = {2, 1, 3, -1, -1, -1, 4};
int n = sizeof(arr) / sizeof(arr[0]);
// 调用 isBST 函数判断是否为二叉搜索树
bool result = isBST(arr, 0, INT_MIN, INT_MAX, n);
// 输出结果
if (result) {
cout << "The binary tree is a Binary Search Tree (BST)." << endl;
} else {
cout << "The binary tree is not a BST." << endl;
}
return 0;
}