Euler 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, ...

Find the sum of all the even-valued terms in the sequence which do not exceed four million.

Powershell Solution:

1. $n1 = 1 
2. $n2 = 1 
3. $sum = 0 
4. while(($n1+$n2) -lt 4e+6) 
5. { 
6.     if($n2 -gt $n1) 
7.     { 
8.         $n1=$n1+$n2 
9.         if($n1%2 -eq 0) 
10.         { 
11.             $sum = $sum + $n1 
12.         } 
13.     } 
14.     else 
15.     { 
16.         $n2=$n1+$n2 
17.         if($n2%2 -eq 0) 
18.         { 
19.             $sum = $sum + $n2 
20.         } 
21.     } 
22. }  
23. $sum 

$sum = 4613732

The above solution doesn’t look that elegant though…
I think it can still be optimized… but anyway, I’ll try again if I have the time…