From e52e39b6e4e8687528f624784c7e867d8ced8457 Mon Sep 17 00:00:00 2001
From: Mattrixwv <m_ellison@ymail.com>
Date: Fri, 11 Sep 2020 11:41:09 -0400
Subject: [PATCH] Added solution to problem 25

---
 ProjectEulerCS/ProblemSelection.cs   |   3 +-
 ProjectEulerCS/Problems/Problem25.cs | 103 +++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 1 deletion(-)
 create mode 100644 ProjectEulerCS/Problems/Problem25.cs

diff --git a/ProjectEulerCS/ProblemSelection.cs b/ProjectEulerCS/ProblemSelection.cs
index 93aa04f..57ee2c2 100644
--- a/ProjectEulerCS/ProblemSelection.cs
+++ b/ProjectEulerCS/ProblemSelection.cs
@@ -32,7 +32,7 @@ namespace ProjectEulerCS{
 		private static readonly List<int> _PROBLEM_NUMBERS = new List<int>()
 				{ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
 				 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
-				 20, 21, 22, 23, 24, 67};
+				 20, 21, 22, 23, 24, 25, 67};
 		public static System.Collections.Generic.List<int> PROBLEM_NUMBERS{
 			get { return _PROBLEM_NUMBERS; }
 		}
@@ -65,6 +65,7 @@ namespace ProjectEulerCS{
 				case 22: problem = new Problem22(); break;
 				case 23: problem = new Problem23(); break;
 				case 24: problem = new Problem24(); break;
+				case 25: problem = new Problem25(); break;
 				case 67: problem = new Problem67(); break;
 			}
 			return problem;
diff --git a/ProjectEulerCS/Problems/Problem25.cs b/ProjectEulerCS/Problems/Problem25.cs
new file mode 100644
index 0000000..5862506
--- /dev/null
+++ b/ProjectEulerCS/Problems/Problem25.cs
@@ -0,0 +1,103 @@
+//ProjectEuler/ProjectEulerCS/src/Problems/Problem25.cs
+//Matthew Ellison
+// Created: 09-11-20
+//Modified: 09-11-20
+//What is the index of the first term in the Fibonacci sequence to contain 1000 digits?
+//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/CSClasses
+/*
+	Copyright (C) 2020  Matthew Ellison
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+
+	You should have received a copy of the GNU Lesser General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+
+using System.Numerics;
+
+
+namespace ProjectEulerCS.Problems{
+	public class Problem25 : Problem{
+		//Variables
+		//Static variables
+		private const int NUM_DIGITS = 1000;	//The number of digits to calculate up to
+		//Instance variables
+		private BigInteger number;	//The current Fibonacci number
+		private BigInteger index;	//The index of the current Fibonacci number just calculated
+		public BigInteger Number{
+			get{
+				if(!solved){
+					throw new Unsolved();
+				}
+				return number;
+			}
+		}
+		public BigInteger Index{
+			get{
+				if(!solved){
+					throw new Unsolved();
+				}
+				return index;
+			}
+		}
+		public override string Result{
+			get{
+				if(!solved){
+					throw new Unsolved();
+				}
+				return $"The first Fibonacci number with {NUM_DIGITS} digits is {number}\nIts index is {index}";
+			}
+		}
+
+		//Functions
+		//Constructor
+		public Problem25() : base($"What is the index of the first term in the Fibonacci sequence to contain {NUM_DIGITS} digits?"){
+			number = 0;
+			index = 2;
+		}
+		//Operational functions
+		//Solve the problem
+		public override void Solve(){
+			//If the problem has already been solved do nothing and end the function
+			if(solved){
+				return;
+			}
+
+			//Star the timer
+			timer.Start();
+
+			//Move through all Fibonacci numbers until you reach the one with at least NUM_DIGITS digits
+			while(number.ToString().Length < NUM_DIGITS){
+				index += 1;	//Increase the index number. Doing this at the beginning keeps the index correct at the end of the loop
+				number = mee.Algorithms.GetFib(index);	//Calculate the number
+			}
+
+			//Stop the timer
+			timer.Stop();
+
+			//THrow a flag to show the porblem is solved
+			solved = true;
+		}
+		//Reset the problem so it can be run again
+		public override void Reset(){
+			base.Reset();
+			number = 0;
+			index = 2;
+		}
+	}
+}
+
+/* Results:
+The first Fibonacci number with 1000 digits is 1070066266382758936764980584457396885083683896632151665013235203375314520604694040621889147582489792657804694888177591957484336466672569959512996030461262748092482186144069433051234774442750273781753087579391666192149259186759553966422837148943113074699503439547001985432609723067290192870526447243726117715821825548491120525013201478612965931381792235559657452039506137551467837543229119602129934048260706175397706847068202895486902666185435124521900369480641357447470911707619766945691070098024393439617474103736912503231365532164773697023167755051595173518460579954919410967778373229665796581646513903488154256310184224190259846088000110186255550245493937113651657039447629584714548523425950428582425306083544435428212611008992863795048006894330309773217834864543113205765659868456288616808718693835297350643986297640660000723562917905207051164077614812491885830945940566688339109350944456576357666151619317753792891661581327159616877487983821820492520348473874384736771934512787029218636250627816
+Its index is 4782
+It took an average of 1.008 seconds to run this problem through 100 iterations
+*/