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Added some algorithms to a class
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503
mattrixwv/Algorithms.java
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503
mattrixwv/Algorithms.java
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//Java/JavaClasses/Algorithms.java
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//Matthew Ellison
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// Created: 03-02-19
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//Modified: 03-02-19
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//This class holds many algorithms that I have found it useful to keep around
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//As such all of the functions in here are static and meant to be used as stand alone functions
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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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package mattrixwv;
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import java.util.Arrays;
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import java.math.BigInteger;
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import java.util.ArrayList;
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import java.util.Collections;
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public class Algorithms{
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//This function returns a list with all the prime numbers <= goalNumber
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public static ArrayList<Integer> getPrimes(Integer goalNumber){
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ArrayList<Integer> primes = new ArrayList<Integer>(); //Holds the prime numbers
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Boolean foundFactor = false; //A flag for whether a factor of the current number has been found
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//If the numebr is 0 or negative return an empty list
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if(goalNumber <= 1){
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return primes;
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}
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//Otherwise the number is at least 2, so 2 should be added to the list
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else{
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primes.add(2);
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}
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//We cna now start at 3 and skipp all even numbers, because they cannot be prime
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for(int possiblePrime = 3;possiblePrime <= goalNumber;possiblePrime += 2){
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//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
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Double topPossibleFactor = Math.ceil(Math.sqrt(possiblePrime));
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//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
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for(int primesCnt = 0;primes.get(primesCnt) <= topPossibleFactor.intValue();){
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if((possiblePrime % primes.get(primesCnt)) == 0){
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foundFactor = true;
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break;
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}
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else{
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++primesCnt;
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}
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//Check if the index has gone out of range
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if(primesCnt >= primes.size()){
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break;
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}
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}
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//If you didn't find a factor then the current number must be prime
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if(!foundFactor){
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primes.add(possiblePrime);
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}
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else{
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foundFactor = false;
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}
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}
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//Sort the list before returning it
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Collections.sort(primes);
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return primes;
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}
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public static ArrayList<BigInteger> getPrimes(BigInteger goalNumber){
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ArrayList<BigInteger> primes = new ArrayList<BigInteger>(); //Holds the prime numbers
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Boolean foundFactor = false; //A flag for whether a factor of the current number has been found
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//If the numeber is 1, 0 or negative return an empty list
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if(goalNumber.compareTo(BigInteger.valueOf(1)) <= 0){
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return primes;
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}
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//Otherwise the number is at least 2, so 2 should be added to the list
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else{
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primes.add(BigInteger.valueOf(2));
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}
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//We cna now start at 3 and skipp all even numbers, because they cannot be prime
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for(BigInteger possiblePrime = BigInteger.valueOf(3);possiblePrime.compareTo(goalNumber) <= 0;possiblePrime = possiblePrime.add(BigInteger.valueOf(2))){
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//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
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BigInteger topPossibleFactor = possiblePrime.sqrt().add(BigInteger.valueOf(1));
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//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
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for(int primesCnt = 0;primes.get(primesCnt).compareTo(topPossibleFactor) <= 0;){
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if((possiblePrime.mod(primes.get(primesCnt))) == BigInteger.valueOf(0)){
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foundFactor = true;
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break;
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}
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else{
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++primesCnt;
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}
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//Check if the index has gone out of range
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if(primesCnt >= primes.size()){
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break;
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}
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}
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//If you didn't find a factor then the current number must be prime
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if(!foundFactor){
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primes.add(possiblePrime);
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}
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else{
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foundFactor = false;
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}
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}
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//Sort the list before returning it
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Collections.sort(primes);
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return primes;
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}
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//This function gets a certain number of primes
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public static ArrayList<Integer> getNumPrimes(int numberOfPrimes){
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ArrayList<Integer> primes = new ArrayList<Integer>(); //Holds the prime numbers
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Boolean foundFactor = false; //A flag for whether a factor of the current number has been found
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//If the numebr is 0 or negative return an empty list
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if(numberOfPrimes <= 1){
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return primes;
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}
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//Otherwise the number is at least 2, so 2 should be added to the list
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else{
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primes.add(2);
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}
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//We cna now start at 3 and skipp all even numbers, because they cannot be prime
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for(int possiblePrime = 3;primes.size() < numberOfPrimes;possiblePrime += 2){
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//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
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Double topPossibleFactor = Math.ceil(Math.sqrt(possiblePrime));
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//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
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for(int primesCnt = 0;primes.get(primesCnt) <= topPossibleFactor.intValue();){
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if((possiblePrime % primes.get(primesCnt)) == 0){
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foundFactor = true;
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break;
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}
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else{
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++primesCnt;
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}
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//Check if the index has gone out of range
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if(primesCnt >= primes.size()){
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break;
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}
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}
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//If you didn't find a factor then the current number must be prime
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if(!foundFactor){
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primes.add(possiblePrime);
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}
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else{
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foundFactor = false;
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}
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}
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//Sort the list before returning it
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Collections.sort(primes);
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return primes;
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}
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public static ArrayList<BigInteger> getNumPrimes(BigInteger numberOfPrimes){
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ArrayList<BigInteger> primes = new ArrayList<BigInteger>(); //Holds the prime numbers
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Boolean foundFactor = false; //A flag for whether a factor of the current number has been found
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//If the numebr is 0 or negative return an empty list
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if(numberOfPrimes.compareTo(BigInteger.valueOf(1)) <= 0){
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return primes;
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}
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//Otherwise the number is at least 2, so 2 should be added to the list
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else{
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primes.add(BigInteger.valueOf(2));
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}
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//We cna now start at 3 and skipp all even numbers, because they cannot be prime
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for(BigInteger possiblePrime = BigInteger.valueOf(3);numberOfPrimes.compareTo((BigInteger.valueOf(primes.size()))) > 0;possiblePrime = possiblePrime.add(BigInteger.valueOf(2))){
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//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
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BigInteger topPossibleFactor = possiblePrime.sqrt().add(BigInteger.valueOf(1));
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//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
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for(int primesCnt = 0;primes.get(primesCnt).compareTo(topPossibleFactor) <= 0;){
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if((possiblePrime.mod(primes.get(primesCnt))) == BigInteger.valueOf(0)){
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foundFactor = true;
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break;
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}
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else{
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++primesCnt;
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}
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//Check if the index has gone out of range
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if(primesCnt >= primes.size()){
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break;
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}
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}
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//If you didn't find a factor then the current number must be prime
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if(!foundFactor){
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primes.add(possiblePrime);
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}
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else{
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foundFactor = false;
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}
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}
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//Sort the list before returning it
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Collections.sort(primes);
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return primes;
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}
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//This function returns all factors of goalNumber
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public static ArrayList<Integer> getFactors(int goalNumber){
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//You need to get all the primes that could be factors of this number so you can test them
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Double topPossiblePrime = Math.ceil(Math.sqrt(goalNumber));
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ArrayList<Integer> primes = getPrimes(topPossiblePrime.intValue());
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ArrayList<Integer> factors = new ArrayList<Integer>();
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//You need to step through each prime and see if it is a factor in the number
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for(int cnt = 0;cnt < primes.size();){
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//If the prime is a factor you need to add it to the factor list
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if((goalNumber % primes.get(cnt)) == 0){
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factors.add(primes.get(cnt));
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goalNumber /= primes.get(cnt);
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}
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//Otherwise advance the location in primes you are looking at
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//By not advancing if the prime is a factor you allow for multiple of the same prime number as a factor
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else{
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++cnt;
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}
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}
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//If you didn't get any factors the number itself must be a prime
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if(factors.size() == 0){
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factors.add(goalNumber);
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goalNumber /= goalNumber;
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}
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//If for some reason the goalNumber is not 1 throw an error
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///Need to add the appropriate error here
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//Return the list of factors
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return factors;
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}
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public static ArrayList<BigInteger> getFactors(BigInteger goalNumber){
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//You need to get all the primes that could be factors of this number so you can test them
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BigInteger topPossiblePrime = goalNumber.sqrt();
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ArrayList<BigInteger> primes = getPrimes(topPossiblePrime);
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ArrayList<BigInteger> factors = new ArrayList<BigInteger>();
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//You need to step through each prime and see if it is a factor in the number
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for(int cnt = 0;cnt < primes.size();){
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//If the prime is a factor you need to add it to the factor list
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if((goalNumber.mod(primes.get(cnt))).compareTo(BigInteger.valueOf(0)) == 0){
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factors.add(primes.get(cnt));
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goalNumber = goalNumber.divide(primes.get(cnt));
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}
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//Otherwise advance the location in primes you are looking at
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//By not advancing if the prime is a factor you allow for multiple of the same prime number as a factor
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else{
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++cnt;
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}
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}
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//If you didn't get any factors the number itself must be a prime
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if(factors.size() == 0){
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factors.add(goalNumber);
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goalNumber.divide(goalNumber);
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}
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//If for some reason the goalNumber is not 1 throw an error
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///Need to add the appropriate error here
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//Return the list of factors
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return factors;
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}
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//This function returns all the divisors of goalNumber
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public static ArrayList<Integer> getDivisors(int goalNumber){
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ArrayList<Integer> divisors = new ArrayList<Integer>();
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//Start by checking that the number is positive
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if(goalNumber <= 0){
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return divisors;
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}
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//If the number is 1 return just itself
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else if(goalNumber == 1){
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divisors.add(1);
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}
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//Otherwise add 1 and itself to the list
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else{
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divisors.add(1);
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divisors.add(goalNumber);
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}
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//Start at 3 and loop through all numbers < sqrt(goalNumber) looking for a number that divides it evenly
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Double topPossibleDivisor = Math.ceil(Math.sqrt(goalNumber));
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for(Integer possibleDivisor = 2;possibleDivisor <= topPossibleDivisor;++possibleDivisor){
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//If you find one add it and the number it creates to the list
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if((goalNumber % possibleDivisor) == 0){
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divisors.add(possibleDivisor);
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//Accound for the possibility of sqrt(goalNumber) being a divisor
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if(possibleDivisor != topPossibleDivisor.intValue()){
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divisors.add(goalNumber / possibleDivisor);
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}
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}
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}
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//Sort the list before returning it for neatness
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Collections.sort(divisors);
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//Return the list
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return divisors;
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}
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public static ArrayList<BigInteger> getDivisors(BigInteger goalNumber){
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ArrayList<BigInteger> divisors = new ArrayList<BigInteger>();
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//Start by checking that the number is positive
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if(goalNumber.compareTo(BigInteger.valueOf(0)) <= 0){
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return divisors;
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}
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//If the number is 1 return just itself
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else if(goalNumber.equals(BigInteger.valueOf(1))){
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divisors.add(BigInteger.valueOf(1));
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}
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//Otherwise add 1 and itself to the list
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else{
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divisors.add(BigInteger.valueOf(1));
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divisors.add(goalNumber);
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}
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//Start at 3 and loop through all numbers < sqrt(goalNumber) looking for a number that divides it evenly
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BigInteger topPossibleDivisor = goalNumber.sqrt();
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for(BigInteger possibleDivisor = BigInteger.valueOf(2);possibleDivisor.compareTo(topPossibleDivisor) <= 0;possibleDivisor = possibleDivisor.add(BigInteger.valueOf(1))){
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//If you find one add it and the number it creates to the list
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if(goalNumber.mod(possibleDivisor).equals(BigInteger.valueOf(0))){
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divisors.add(possibleDivisor);
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//Accound for the possibility of sqrt(goalNumber) being a divisor
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if(!possibleDivisor.equals(topPossibleDivisor)){
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divisors.add(goalNumber.divide(possibleDivisor));
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}
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}
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}
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//Sort the list before returning it for neatness
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Collections.sort(divisors);
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//Return the list
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return divisors;
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}
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//This function returns all the divisors of goalNumber
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public static Integer getFib(int goalSubscript){
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//Setup the variables
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Integer[] fibNums = {1, 1, 0}; //A list to keep track of the Fibonacci numbers. It need only be 3 long because we only need the one we are working on and the last 2
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//If the number is <= 0 return 0
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if(goalSubscript <= 0){
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return 0;
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}
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//Loop through the list, generating Fibonacci numbers until it finds the correct subscript
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Integer fibLoc = 2;
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for(fibLoc = 2;fibLoc < goalSubscript;++fibLoc){
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fibNums[fibLoc % 3] = fibNums[(fibLoc - 1) % 3] + fibNums[(fibLoc - 2) % 3];
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}
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//Return the propper number. The location counter is 1 off of the subscript
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return fibNums[(fibLoc - 1) % 3];
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}
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public static BigInteger getFib(BigInteger goalSubscript){
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//Setup the variables
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BigInteger[] fibNums = {BigInteger.valueOf(1), BigInteger.valueOf(1), BigInteger.valueOf(0)}; //A list to keep track of the Fibonacci numbers. It need only be 3 long because we only need the one we are working on and the last 2
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//If the number is <= 0 return 0
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if(goalSubscript.compareTo(BigInteger.valueOf(0)) <= 0){
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return BigInteger.valueOf(0);
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}
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//Loop through the list, generating Fibonacci numbers until it finds the correct subscript
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Integer fibLoc = 2;
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for(fibLoc = 2;goalSubscript.compareTo(BigInteger.valueOf(fibLoc)) > 0;++fibLoc){
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fibNums[fibLoc % 3] = fibNums[(fibLoc - 1) % 3].add(fibNums[(fibLoc - 2) % 3]);
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}
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//Return the propper number. The location counter is 1 off of the subscript
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return fibNums[(fibLoc - 1) % 3];
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}
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//This function returns a list of all Fibonacci numbers <= goalNumber
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public static ArrayList<Integer> getAllFib(int goalNumber){
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//Setup the variables
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ArrayList<Integer> fibNums = new ArrayList<Integer>(); //A list to save the Fibonacci numbers
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//If the number is <= 0 return an empty list
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if(goalNumber <= 0){
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return fibNums;
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}
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//This means that at least 2 1's are elements
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fibNums.add(1);
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fibNums.add(1);
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//Loop to generate the rest of the Fibonacci numbers
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while(fibNums.get(fibNums.size() - 1) <= goalNumber){
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fibNums.add(fibNums.get(fibNums.size() - 1) + fibNums.get(fibNums.size() - 2));
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}
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//At this point the most recent number is > goalNumber, so remove it and return the rest of the list
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fibNums.remove(fibNums.size() - 1);
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return fibNums;
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}
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public static ArrayList<BigInteger> getAllFib(BigInteger goalNumber){
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//Setup the variables
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ArrayList<BigInteger> fibNums = new ArrayList<BigInteger>(); //A list to save the Fibonacci numbers
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//If the number is <= 0 return an empty list
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if(goalNumber.compareTo(BigInteger.valueOf(0)) <= 0){
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return fibNums;
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}
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//This means that at least 2 1's are elements
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fibNums.add(BigInteger.valueOf(1));
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fibNums.add(BigInteger.valueOf(1));
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//Loop to generate the rest of the Fibonacci numbers
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while(fibNums.get(fibNums.size() - 1).compareTo(goalNumber) <= 0){
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fibNums.add(fibNums.get(fibNums.size() - 1).add(fibNums.get(fibNums.size() - 2)));
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||||
}
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//At this point the most recent number is > goalNumber, so remove it and return the rest of the list
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fibNums.remove(fibNums.size() - 1);
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return fibNums;
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}
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//This function returns the sum of all elements in the list
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public static int getSum(ArrayList<Integer> nums){
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//If a blank list was passed to the function return 0 as the sum
|
||||
if(nums.size() == 0){
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||||
return 0;
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||||
}
|
||||
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||||
//Setup the variables
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||||
Integer sum = 0;
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||||
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||||
//Loop through every element in the list and add them together
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||||
for(Integer num : nums){
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||||
sum += num;
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||||
}
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||||
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||||
//Return the sum of all elements
|
||||
return sum;
|
||||
}
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||||
public static BigInteger getBigSum(ArrayList<BigInteger> nums){
|
||||
//If a blank list was passed to the function return 0 as the sum
|
||||
if(nums.size() == 0){
|
||||
return BigInteger.valueOf(0);
|
||||
}
|
||||
|
||||
//Setup the variables
|
||||
BigInteger sum = BigInteger.valueOf(0);
|
||||
|
||||
//Loop through every element in the list and add them together
|
||||
for(BigInteger num : nums){
|
||||
sum = sum.add(num);
|
||||
}
|
||||
|
||||
//Return the sum of all elements
|
||||
return sum;
|
||||
}
|
||||
//This function returns the product of all elements in the list
|
||||
public static int getProd(ArrayList<Integer> nums){
|
||||
//If a blank list was passed tot he fuction return 0 as the product
|
||||
if(nums.size() == 0){
|
||||
return 0;
|
||||
}
|
||||
|
||||
//Setup the variables
|
||||
Integer product = 1; //Start at 1 because x * 1 = x
|
||||
|
||||
//Loop through every element in the list and multiply them together
|
||||
for(Integer num : nums){
|
||||
product *= num;
|
||||
}
|
||||
|
||||
//Return the product of all elements
|
||||
return product;
|
||||
}
|
||||
public static BigInteger getBigProd(ArrayList<BigInteger> nums){
|
||||
//If a blank list was passed tot he fuction return 0 as the product
|
||||
if(nums.size() == 0){
|
||||
return BigInteger.valueOf(0);
|
||||
}
|
||||
|
||||
//Setup the variables
|
||||
BigInteger product = BigInteger.valueOf(1); //Start at 1 because x * 1 = x
|
||||
|
||||
//Loop through every element in the list and multiply them together
|
||||
for(BigInteger num : nums){
|
||||
product = product.multiply(num);
|
||||
}
|
||||
|
||||
//Return the product of all elements
|
||||
return product;
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user