Added getFib functions

Algorithms.lua

@@ -172,6 +172,48 @@ function getDivisors(goalNumber)
 	return divisors;
 end
 
+--This function returns the numth Fibonacci number
+function getFib(goalSubscript)
+	--Setup the variables
+	local fibNums = {1, 1, 0};	--A list to keep track of the Fibonacci Numbers. It need only be 3 long because we only need the one we are working on and the last 2
+
+	--If the number is <= 0 return 0
+	if(goalSubscript <= 0) then
+		return 0;
+	end
+
+	--Loop through the list, generating Fibonacci numbers until it finds the correct subscript
+	local fibLoc = 3;
+	while(fibLoc <= goalSubscript) do
+		fibNums[fibLoc % 3] = fibNums[(fibLoc - 1) % 3] + fibNums[(fibLoc - 2) % 3];
+		fibLoc = fibLoc + 1;
+	end
+
+	--Return the propper number
+	return fibNums[(fibLoc - 1) % 3];
+end
+
+function getLargeFib(goalSubscript)
+	local bigint = require "bigint";
+	--Setup the variables
+	local fibNums = {bigint.new(1), bigint.new(1), bigint.new(0)};
+
+	--If the number <= 0 return 0
+	if(goalSubscript <= 0) then
+		return bigint.new(0);
+	end
+
+	--Loop through the list, generating Fibonacci numbers until it finds the correct subscript
+	local fibLoc = 3;
+	while(fibLoc <= goalSubscript) do
+		fibNums[fibLoc % 3] = bigint.add(fibNums[(fibLoc - 1) % 3], fibNums[(fibLoc - 2) % 3]);
+		fibLoc = fibLoc + 1;
+	end
+
+	--Return the propper number
+	return fibNums[(fibLoc - 1) % 3];
+end
+
 function getSum(ary)
 	local sum = 0;	--Holds the sum of all elements. Start at 0 because num+1 = num
 	--Look through every element in the array and add the number to the running sum