Added solution to problem 14

This commit is contained in:
2020-08-24 21:15:10 -04:00
parent fb764f32fb
commit 6b8c6e0266
3 changed files with 124 additions and 2 deletions

View File

@@ -31,7 +31,7 @@ namespace ProjectEulerCS{
//Holds the valid problem numbers
private static readonly List<int> _PROBLEM_NUMBERS = new List<int>()
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13};
10, 11, 12, 13, 14};
public static System.Collections.Generic.List<int> PROBLEM_NUMBERS{
get { return _PROBLEM_NUMBERS; }
}
@@ -53,6 +53,7 @@ namespace ProjectEulerCS{
case 11: problem = new Problem11(); break;
case 12: problem = new Problem12(); break;
case 13: problem = new Problem13(); break;
case 14: problem = new Problem14(); break;
}
return problem;
}

View File

@@ -1,4 +1,4 @@
//ProjectEuler/ProjectEulerCS/src/Problems/Problem12.cs
//ProjectEuler/ProjectEulerCS/src/Problems/Problem13.cs
//Matthew Ellison
// Created: 08-24-20
//Modified: 08-24-20

View File

@@ -0,0 +1,121 @@
//ProjectEuler/ProjectEulerCS/src/Problems/Problem14.cs
//Matthew Ellison
// Created: 08-24-20
//Modified: 08-24-20
/*
The following iterative sequence is defined for the set of positive integers:
n → n/2 (n is even)
n → 3n + 1 (n is odd)
Which starting number, under one million, produces the longest chain?
*/
//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/>.
*/
namespace ProjectEulerCS.Problems{
public class Problem14 : Problem{
//Variables
//Static variables
private const long MAX_NUM = 1000000 - 1; //This is the top number that you will be checking against the series
//Instance variables
private long maxLength; //This is the length of the longest chain
public long Length{
get{
if(!solved){
throw new Unsolved();
}
return maxLength;
}
}
private long maxNum; //This is the starting number of the longest chain
public long StartingNumber{
get{
if(!solved){
throw new Unsolved();
}
return maxNum;
}
}
//Functions
//Constructor
public Problem14() : base("Which starting number, under one million, produces the longest chain using the itterative sequence?"){
maxLength = 0;
maxNum = 0;
}
//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;
}
//Start the timer
_timer.Start();
//Loop through all numbers <= MAX_NUM and check them against the series
for(long currentNum = 1;currentNum <= MAX_NUM;++currentNum){
long currentLength = CheckSeries(currentNum);
//If the current number has a longer series than the max then the current becomes the max
if(currentLength > maxLength){
maxLength = currentLength;
maxNum = currentNum;
}
}
//Stop the timer
_timer.Stop();
//Throw a flag to show the problem is solved
solved = true;
//Save the results
_result = "The number " + maxNum + " produced a chain of " + maxLength + " steps";
}
//This function follows the rules of the sequence and returns its length
private long CheckSeries(long num){
long length = 1; //Start at 1 because you need to count the starting number
//Follow the series, adding 1 for each time you take
while(num > 1){
if((num % 2) == 0){
num /= 2;
}
else{
num = (3 * num) + 1;
}
++length;
}
//Return the length of the series
return length;
}
//Reset the problem so it can be run again
public override void Reset(){
base.Reset();
maxLength = 0;
maxNum = 0;
}
}
}
/* Results:
The number 837799 produced a chain of 525 steps
It took an average of 249.883 milliseconds to run this problem through 100 iterations
*/