/// <summary>
/// Computes the smallest Fibonacci number that is greater than <paramref name="number"/>.
/// Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...
/// </summary>
/// <param name="number">The integer we want to compute the closest Fibonacci to it that is bigger than or equal to it. </param>
/// <returns>The Fibonacci number.</returns>
public static FibonacciElement GetSmallestFibonacciBiggerThanNumber(int number)
{
var fib = new FibonacciElement(0, 1);
while (fib.FibN < number)
{
fib.ShiftForward();
}
return(fib);
}
public static int Search <T>(List <T> sortedList, T key) where T : IComparable <T>
{
/* If key is NOT in the range, terminate search. Since the input list is sorted this early check is feasible. */
if (key.CompareTo(sortedList[0]) < 0 || key.CompareTo(sortedList[sortedList.Count - 1]) > 0)
{
return(-1);
}
FibonacciElement fib = GetSmallestFibonacciBiggerThanNumber(sortedList.Count);
int startIndex = -1;
/* Note that fib numbers indicate indexes in the list to look at, and not values. */
while (fib.FibN > 1) /* meaning in the sequence {0, 1, 1, 2, 3, ...} the while loop will stop when fibN = 2, thus fibN2 can at least be 1 */
{
/* First compare to the value at index FibN2 */
int index = Math.Min(startIndex + fib.FibN2, sortedList.Count - 1);
if (key.CompareTo(sortedList[index]) == 0)
{
return(index);
}
if (key.CompareTo(sortedList[index]) < 0)
{
// Shift backward twice as checked against FibN2
fib.ShiftBackward();
fib.ShiftBackward();
}
if (key.CompareTo(sortedList[index]) > 0)
{
fib.ShiftBackward();
startIndex = index; /* Which is the previous Fib2*/
}
}
if (fib.FibN1 == 1 && (startIndex + 1) < sortedList.Count && sortedList[startIndex + 1].CompareTo(key) == 0)
{
return(startIndex + 1);
}
return(-1);
}
