Upper bound using BS

ll upper_bound(vector<ll>v, ll l, ll r, ll x)
{
    ll index=-1;
    while(r>=l)
    {
        ll mid=(l+r)/2;
        if(v[mid]>x)
        {
            index=mid;
            r=mid-1;
        }
        else
            l=mid+1;
    }
    return index-1;
}