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Added solution to problem 14
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@@ -31,7 +31,7 @@ namespace ProjectEulerCS{
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//Holds the valid problem numbers
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private static readonly List<int> _PROBLEM_NUMBERS = new List<int>()
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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10, 11, 12, 13};
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10, 11, 12, 13, 14};
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public static System.Collections.Generic.List<int> PROBLEM_NUMBERS{
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get { return _PROBLEM_NUMBERS; }
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}
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@@ -53,6 +53,7 @@ namespace ProjectEulerCS{
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case 11: problem = new Problem11(); break;
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case 12: problem = new Problem12(); break;
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case 13: problem = new Problem13(); break;
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case 14: problem = new Problem14(); break;
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}
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return problem;
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}
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@@ -1,4 +1,4 @@
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//ProjectEuler/ProjectEulerCS/src/Problems/Problem12.cs
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//ProjectEuler/ProjectEulerCS/src/Problems/Problem13.cs
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//Matthew Ellison
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// Created: 08-24-20
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//Modified: 08-24-20
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121
ProjectEulerCS/Problems/Problem14.cs
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121
ProjectEulerCS/Problems/Problem14.cs
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@@ -0,0 +1,121 @@
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//ProjectEuler/ProjectEulerCS/src/Problems/Problem14.cs
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//Matthew Ellison
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// Created: 08-24-20
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//Modified: 08-24-20
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/*
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The following iterative sequence is defined for the set of positive integers:
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n → n/2 (n is even)
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n → 3n + 1 (n is odd)
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Which starting number, under one million, produces the longest chain?
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*/
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//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/CSClasses
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/*
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Copyright (C) 2020 Matthew Ellison
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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namespace ProjectEulerCS.Problems{
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public class Problem14 : Problem{
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//Variables
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//Static variables
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private const long MAX_NUM = 1000000 - 1; //This is the top number that you will be checking against the series
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//Instance variables
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private long maxLength; //This is the length of the longest chain
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public long Length{
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get{
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if(!solved){
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throw new Unsolved();
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}
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return maxLength;
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}
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}
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private long maxNum; //This is the starting number of the longest chain
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public long StartingNumber{
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get{
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if(!solved){
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throw new Unsolved();
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}
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return maxNum;
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}
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}
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//Functions
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//Constructor
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public Problem14() : base("Which starting number, under one million, produces the longest chain using the itterative sequence?"){
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maxLength = 0;
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maxNum = 0;
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}
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//Operational functions
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//Solve the problem
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public override void Solve(){
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//If the problem has already been solved do nothing and end the function
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if(solved){
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return;
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}
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//Start the timer
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_timer.Start();
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//Loop through all numbers <= MAX_NUM and check them against the series
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for(long currentNum = 1;currentNum <= MAX_NUM;++currentNum){
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long currentLength = CheckSeries(currentNum);
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//If the current number has a longer series than the max then the current becomes the max
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if(currentLength > maxLength){
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maxLength = currentLength;
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maxNum = currentNum;
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}
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}
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//Stop the timer
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_timer.Stop();
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//Throw a flag to show the problem is solved
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solved = true;
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//Save the results
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_result = "The number " + maxNum + " produced a chain of " + maxLength + " steps";
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}
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//This function follows the rules of the sequence and returns its length
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private long CheckSeries(long num){
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long length = 1; //Start at 1 because you need to count the starting number
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//Follow the series, adding 1 for each time you take
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while(num > 1){
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if((num % 2) == 0){
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num /= 2;
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}
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else{
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num = (3 * num) + 1;
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}
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++length;
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}
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//Return the length of the series
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return length;
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}
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//Reset the problem so it can be run again
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public override void Reset(){
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base.Reset();
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maxLength = 0;
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maxNum = 0;
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}
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}
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}
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/* Results:
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The number 837799 produced a chain of 525 steps
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It took an average of 249.883 milliseconds to run this problem through 100 iterations
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*/
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