Files
ProjectEulerJava/Problem26.java

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3.3 KiB
Java

//ProjectEuler/Java/Problem26.java
//Matthew Ellison
// Created: 07-28-19
//Modified: 07-28-19
//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/JavaClasses
/*
Copyright (C) 2019 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/>.
*/
import mattrixwv.Stopwatch;
import mattrixwv.Algorithms;
import java.util.ArrayList;
public class Problem26{
private static final Integer TOP_NUM = 999;
public static void main(String[] args){
//Setup the variables
Stopwatch timer = new Stopwatch();
Integer longestCycle = 0; //The length of the longest cycle
Integer longestNumber = 0; //The starting denominator of the longest cycle
//Start the timer
timer.start();
//Start with 1/2 and find out how long the longest cycle is by checking the remainders
//Loop through every number from 2-999 and use it for the denominator
for(Integer denominator = 2;denominator <= TOP_NUM;++denominator){
ArrayList<Integer> denomList = new ArrayList<Integer>();
Boolean endFound = false; //Holds whether we have found an end to the number (either a cycle or a 0 for remainder)
Boolean cycleFound = false; //Holds whether a cycle was detected
Integer numerator = 1; //The numberator that will be divided. Always starts at 1
while(!endFound){
//Get the remainder after the division
Integer remainder = numerator % denominator;
//Check if the remainder is 0
//If it is set the flag
if(remainder.equals(0)){
endFound = true;
}
//Check if the remainder is in the list
//If it is in the list, set the appropriate flags
else if(Algorithms.isFound(denomList, remainder)){
endFound = true;
cycleFound = true;
}
//Else add it to the list
else{
denomList.add(remainder);
}
//Multiply the remainder by 10 to continue finding the next remainder
numerator = remainder * 10;
}
//If a cycle was found check the size of the list against the largest cycle
if(cycleFound){
//If it is larger than the largest, set it as the new largest
if(denomList.size() > longestCycle){
longestCycle = denomList.size();
longestNumber = denominator;
}
}
}
//Stop the timer
timer.stop();
//Print the restuls
System.out.printf("The longest cycle is %d digits long\n", longestCycle);
System.out.printf("It started with the number %d\n", longestNumber);
System.out.println("It took " + timer.getStr() + " to run this algorithm");
}
}
/* Results:
The longest cycle is 982 digits long
It started with the number 983
It took 41.482 milliseconds to run this algorithm
*/