From aed6b8672caa7f01259b2dc87cb6383444718133 Mon Sep 17 00:00:00 2001
From: Matthew Ellison <m_ellison@ymail.com>
Date: Wed, 14 Nov 2018 00:12:37 -0500
Subject: [PATCH] Added algorithms for finding a Fibonacci number

---
 Algorithms.hpp | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/Algorithms.hpp b/Algorithms.hpp
index 3dfd1d8..e84711a 100644
--- a/Algorithms.hpp
+++ b/Algorithms.hpp
@@ -11,6 +11,7 @@
 #include <cinttypes>
 #include <algorithm>
 #include <string>
+#include <gmp.h>	//This is necessary for the getFib function for numbers larger than a normal int can hold. It can be commented out if needed
 
 namespace mee{
 
@@ -33,6 +34,9 @@ bool isFound(T num, std::vector<T> list);
 //It is meant to have only the string passed into it from the calling function. num is used for recursion purposes
 //It can however be used with num if you want the first num characters to be stationary
 std::vector<std::string> getPermutations(std::string master, int num = 0);
+//These functions return the numth Fibonacci number
+uint64_t getFib(uint64_t num);
+void getFib(mpz_t fibNum, uint64_t num);
 
 
 template<class T>
@@ -143,6 +147,62 @@ std::vector<std::string> getPermutations(std::string master, int num){
 	return perms;
 }
 
+uint64_t getFib(uint64_t num){
+	//Make sure the number is within bounds
+	if(num <= 2){
+		return 1;
+	}
+	//Setup the variables
+	uint64_t fib = 0;
+	uint64_t tempNums[3];
+	tempNums[0] = tempNums[2] = 1;
+
+	//Do the calculation
+	uint64_t cnt = 2;
+	uint64_t location = 1;
+	while(cnt < num){
+		tempNums[location] = tempNums[(location + 1) % 3] + tempNums[(location + 2) % 3];
+		location = (location + 1) % 3;
+		++cnt;
+	}
+	fib = tempNums[(num + 1) % 3];	//Transfer the answer to permanent variable
+	return fib;
+}
+
+void getFib(mpz_t fibNum, uint64_t num){
+	//Make sure the number is within bounds
+	if(num <= 0){
+		mpz_set_ui(fibNum, 0);
+		return;
+	}
+	else if(num <= 2){
+		mpz_set_ui(fibNum, 1);
+		return;
+	}
+	mpz_t tempNums[3];
+	//Initialize the variables
+	mpz_init(tempNums[0]);
+	mpz_init(tempNums[1]);
+	mpz_init(tempNums[2]);
+	//Set the variables correctly
+	mpz_set_ui(tempNums[0], 1);
+	mpz_set_ui(tempNums[2], 1);
+
+	//Do the calculation
+	uint64_t cnt = 2;
+	uint64_t location = 1;
+	while(cnt < num){
+		mpz_add(tempNums[location], tempNums[(location + 1) % 3], tempNums[(location + 2) % 3]);
+		location = (location + 1) % 3;
+		++cnt;
+	}
+	mpz_set(fibNum, tempNums[(num + 1) % 3]);	//Transfer the answer to the permanent variable
+
+	//Clear the variables
+	mpz_clear(tempNums[0]);
+	mpz_clear(tempNums[1]);
+	mpz_clear(tempNums[2]);
+}
 
 }