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evenfibonacci.go
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/
evenfibonacci.go
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package goexercises
import (
"sync"
"github.com/alesr/numbers"
)
// EvenFibonacci - https://projecteuler.net/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.
func EvenFibonacci(limit int) int {
var wg sync.WaitGroup
fib := numbers.FibonacciGen()
sum := 0
mutex := &sync.Mutex{}
for {
f := <-fib
if f < limit {
wg.Add(1)
go func() {
defer wg.Done()
if f%2 == 0 {
mutex.Lock()
sum += f
mutex.Unlock()
}
}()
} else {
wg.Wait()
return sum
}
}
}