public void DigitArray_DigitCountTest()
{
var digitArray = new DigitArray(1);
Assert.AreEqual(1, digitArray.GetDigitCount());
digitArray = new DigitArray(125);
Assert.AreEqual(3, digitArray.GetDigitCount());
}
public void DigitArray_MultiplyByTest()
{
var digitArray = new DigitArray(1);
digitArray.MultiplyBy(9);
Assert.AreEqual(1, digitArray.GetDigitCount());
Assert.AreEqual(9, digitArray.GetDigitSum());
digitArray = new DigitArray(125);
digitArray.MultiplyBy(77); // result = 9625
Assert.AreEqual(4, digitArray.GetDigitCount());
Assert.AreEqual(22, digitArray.GetDigitSum());
}
public void DigitArray_CloneTest()
{
var d = new DigitArray(9999999);
var clone = d.Clone();
Assert.AreEqual(63, clone.GetDigitSum());
Assert.AreEqual(7, clone.GetDigitCount());
clone.MultiplyBy(2); // 19999998
// original is not modified
Assert.AreEqual(63, d.GetDigitSum());
Assert.AreEqual(7, d.GetDigitCount());
// clone is modified
Assert.AreEqual(63, clone.GetDigitSum());
Assert.AreEqual(8, clone.GetDigitCount());
}
public long Solve()
{
var previousFibNumber = new DigitArray(1);
var fibNumber = new DigitArray(1);
var currentNumber = 2;
while (fibNumber.GetDigitCount() < 1000)
{
var temp = fibNumber.Clone();
fibNumber = fibNumber + previousFibNumber;
previousFibNumber = temp;
currentNumber++;
}
return currentNumber;
}
