#include <iostream>
#include <cstdlib>
#include <ctime> 
using namespace std;
 
int BinSearch(const int* arr, int count, int key);
 
int main()
{	
	srand(time(NULL));
	setlocale(0,"");

		int n;
			cout << "Input elements of array: ";
				cin>>n;

		int *arr = new int[n];
		
		for(int i=0;i<n;i++)
			arr[i]=rand()%10;
		int key;
    
		cout << "key: ";
			cin >> key;
 
		for(i=0;i<n;i++){
			cout << arr[i] << endl;
		}

		if(BinSearch(arr, n, key) != -1)
			cout << "Yes" << endl;
		else cout << "No" << endl;
	delete arr;
    
    return 0;
}
 
int BinSearch(const int* arr, int count, int key) 
{
  int l = 0;            // íèæíÿÿ ãðàíèöà
  int u = count - 1;    // âåðõíÿÿ ãðàíèöà
 
  while (l <= u) {
    int m = (l + u) / 2;
    if (arr[m] == key) return m;
    if (arr[m] < key) l = m + 1;
    if (arr[m] > key) u = m - 1;
  }
  return -1;
}