public void Go()
{
var gen = new BigInteger[, ]
{
{ 0, 1 },
{ 1, 1 },
};
var f1 = new BigInteger[, ]
{
{ 0, 0 },
{ 0, 1 },
};
const int desiredLen = 1000;
const int maxN = 100000;
var result = 0;
EnumerableHelper.BinarySearch(maxN, n =>
{
var fibn = GetFib(gen, f1, n);
var len = fibn.ToString().Length;
result = n;
if (len < desiredLen)
{
return(1); // go right
}
return(-1); // go left
});
Console.WriteLine(result);
Console.WriteLine(new { n = 11, len = GetFib(gen, f1, 11).ToString().Length });
Console.WriteLine(new { n = 12, len = GetFib(gen, f1, 12).ToString().Length });
Console.WriteLine(new { n = result - 1, len = GetFib(gen, f1, result - 1).ToString().Length });
Console.WriteLine(new { n = result, len = GetFib(gen, f1, result).ToString().Length });
}
