Problem #2

Problem link
Solution:

package main

func main() {
    a, b, sum := 1, 2, 0
    for b < 4000000 {
        if b%2 == 0 {
            sum += b
        }
        a, b = b, a+b
    }
    println(sum)
}

Result: 4613732
Time: 0m0.003s