#include <iostream>
using namespace std;

int binarySearchDesc(int arr[], int n, int k) {
    int low = 0, high = n - 1;
    while (low <= high) {
        int mid = low + (high - low) / 2;
        if (arr[mid] == k)
            return mid;
        if (arr[mid] < k) // 由于是降序，此处应为小于
            high = mid - 1;
        else
            low = mid + 1;
    }
    return -1; // 查找失败
}

//int main() {
//    int arr[] = {98, 86, 75, 64, 55, 48, 37, 22, 13};
//    int n = sizeof(arr)/sizeof(arr[0]);
//    int k = 22;
//    int result = binarySearchDesc(arr, n, k);
//    if(result != -1)
//        cout << "Element found at index: " << result;
//    else
//        cout << "Element not found";
//    return 0;
//}