static void Main(string[] args)
{
var reader = new ArrayReader(new[] { -1, 0, 3, 5, 9, 12 });
int target = 2;
Console.WriteLine(Search(reader, target));
}
static int Search(ArrayReader reader, int target)
{
int li = 0, hi = 10000;
while (li < hi)
{
int mid = li + (hi - li) / 2;
int num = reader.Get(mid);
if (num == target)
{
return(mid);
}
if (num > target || num == -1)
{
hi = mid;
}
else
{
li = mid + 1;
}
}
return(reader.Get(li) == target ? li : -1);
}