Contest1422/A.cpp

#include<iostream>

using namespace std;

int main() {
    int a[10], k;
    for (int i = 0; i < 10; i++) {
        cin >> a[i];
    }
    cin >> k;
    int left = 0, right = 9;
    bool flag = false;
    while (left <= right) {
        int mid = (left + right) / 2;
        if (a[mid] == k) {
            cout << mid << endl;
            flag = true;
            break;
        } else if (k > a[mid]) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    if (!flag) {
        cout << "Not exist!" << endl;
    }
    return 0;
}