【Project Euler】2 第二题

//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.
    

    static void Main()
        {
            int max = 0;
            int[] num=new int[10000];
            num[0]=1;
            num[1]=2;
            int sum = 2;
           
            for(int i=0;max<4000000;i++)
            {
                num[i + 2] = num[i] + num[i + 1];
                max = num[i + 2];
                if (max % 2 == 0)
                {
                    sum = sum + num[i + 2];
                    if (max > 4000000)
                    {
                        sum = sum - num[i + 2];
                    }
                }
              
            }
            Console.WriteLine(sum);

        }