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63 lines
3.2 KiB
Java
63 lines
3.2 KiB
Java
//ProjectEuler/Java/Problem25.java
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//Matthew Ellison
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// Created: 03-25-19
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//Modified: 03-28-19
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//What is the index of the first term in the Fibonacci sequence to contain 1000 digits?
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//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses
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/*
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Copyright (C) 2019 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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import mattrixwv.Stopwatch;
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import mattrixwv.Algorithms;
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import java.math.BigInteger;
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public class Problem25{
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private static final Integer NUM_DIGITS = 1000; //The number of digits to calculate up to
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public static void main(String[] args){
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//Setup the variables
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Stopwatch timer = new Stopwatch();
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BigInteger number = BigInteger.ZERO; //Holds the current Fibonacci number
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BigInteger index = BigInteger.valueOf(2L); //The index of the Fibonacci number just calculated
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//Start the timer
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timer.start();
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//Move through all Fibonacci numbers until you reach the one with at least NUM_DIGITS digits
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while(number.toString().length() < NUM_DIGITS){
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index = index.add(BigInteger.ONE); //Increase the index number. Doing this at the beginning keeps the index correct at the end of the loop
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number = Algorithms.getFib(index); //Calculate the number
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}
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//Stop the timer
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timer.stop();
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//Print the results
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System.out.printf("The first Fibonacci number with %d digits is %s\n", NUM_DIGITS, number.toString());
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System.out.printf("Its index is %d\n", index);
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System.out.printf("It took %s to run this algorithm\n", timer.getStr());
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}
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}
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/* Results:
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The first Fibonacci number with 1000 digits is 1070066266382758936764980584457396885083683896632151665013235203375314520604694040621889147582489792657804694888177591957484336466672569959512996030461262748092482186144069433051234774442750273781753087579391666192149259186759553966422837148943113074699503439547001985432609723067290192870526447243726117715821825548491120525013201478612965931381792235559657452039506137551467837543229119602129934048260706175397706847068202895486902666185435124521900369480641357447470911707619766945691070098024393439617474103736912503231365532164773697023167755051595173518460579954919410967778373229665796581646513903488154256310184224190259846088000110186255550245493937113651657039447629584714548523425950428582425306083544435428212611008992863795048006894330309773217834864543113205765659868456288616808718693835297350643986297640660000723562917905207051164077614812491885830945940566688339109350944456576357666151619317753792891661581327159616877487983821820492520348473874384736771934512787029218636250627816
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Its index is 4782
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It took 1.182 seconds to run this algorithm
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*/
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