java - 欧拉计划编号2

Question

我尝试了很多次，但我似乎无法弄清楚我做错了什么。这是我最近尝试的解决方案之一。

我从其他来源知道正确答案是4613732。

/*
 *             PROBLEM 2
 * 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.
 */

public class problem2 
{
    public static void main(String args[])
    {
        int sum = 0;

        int[] anArray = new int[4000000];
        anArray[0] = 1;
        anArray[1] = 2;

        for (int i = 2; i <= anArray.length - 1; i++) {
            anArray[i] = anArray[i - 1] + anArray[i - 2];

            if (anArray[i] % 2 == 0 && anArray[i] <= 4000000) {
                sum += anArray[i];
            }
        }
        System.out.println(sum);        
    }
}

Answer 1

首先，你缺少两个其次，为了避免溢出问题:http://en.wikipedia.org/wiki/Integer_overflow ，一旦超过一百万，就应该插入一个break语句。