Project Euler | Problem 2 | Even Fibonacci numbers

Problem Description :

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

Project Euler Problem 2

Concept :

In Fibonacci sequence, each Fibonacci term is a sum of previous two terms.

For example - F(N)=F(N-2)+F(N-1)

Java Program :

package com.javamultiplex.projecteuler; import java.util.ArrayList; import java.util.List; /** * * @author Rohit Agarwal * @category Project Euler Problems * @problem Sum of even valued fibonacci terms below four million. * */ public class Problem2 { public static void main(String[] args) { int limit = 4000000; // 4 million long result = getSumOfEvenFibonacciSequence(limit); System.out.println("The sum of even valued terms of fibonacci sequence " + "whose values do not exceed four million is : " + result); } private static long getSumOfEvenFibonacciSequence(int limit) { List<Integer> fib = new ArrayList<Integer>(); // Default values of first two terms of fibonacci sequence is 1,1. fib.add(0, 1); fib.add(1, 1); int i = 1, temp, evenSum = 0; while (fib.get(i) <= limit) { i++; temp = getNextFibonacciTerm(fib, i); fib.add(i, temp); temp = fib.get(i); if (temp <= limit) { if (temp % 2 == 0) { evenSum += temp; } } } return evenSum; } private static int getNextFibonacciTerm(List<Integer> fib, int i) { // On adding previous 2 terms we can get next fibonacci term. int result = fib.get(i - 1) + fib.get(i - 2); return result; } }

Output :

Output - Project Euler Problem 2

References :

https://projecteuler.net/problem=2

https://en.wikipedia.org/wiki/Fibonacci_number

https://docs.oracle.com/javase/7/docs/api/java/util/ArrayList.html

https://docs.oracle.com/javase/7/docs/api/java/util/List.html

Thank you friends, I hope you have clearly understood the solution of this problem. If you have any doubt, suggestion or query please feel free to comment below. You can also discuss this solution in our forum.

Tags : Project Euler Problem 2 Solution, Mathematics problems, Fibonacci numbers, Solution in Java, List, ArrayList, if statement, Dynamic programming, While loop.

About Author:

I am simple guy with lot of ambitions. My main motive is to share whatever knowledge I have related to programming. With me you can easily learn how to solve any programming problem in Java.You can connect with me on social networking sites also.

Let's Get Connected: Linkedin | Facebook | Google Plus