T50

#include <iostream>

using namespace std;

int main()
{
    int a[20],n,x,k;
    cout<<"n=";
    cin>>n;
    cout<<"x=";
    cin>>x;
    for (int i=0;i<n;i++)
    {
        cout<<"a["<<i<<"]=";
        cin>>a[i];
    }
    int i=0;
    while (i<n)
    {
        k=(i+n-1)/2;
        if (a[k]==x)
        {
            cout<<"van";
            return 0;
        }
        else
        {
            if (x>a[k])
            {
                i=k+1;
            }
            else
            {
                n=k-1;
            }
        }
    }
    if (i>=n)
    {
        cout<<"nem volt";
    }

    return 0;