1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
###
# Even Fibonacci numbers
# 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.
###
using Base.Iterators
cache = Dict()
function fib(n)
if haskey(cache, n)
return cache[n]
end
if n < 3
return n
end
cache[n] = fib(n - 1) + fib(n - 2)
return cache[n]
end
# https://stackoverflow.com/questions/56137634/function-chaining-in-julia
result = (
(fib(n) for n in 1:1_000_000)
|> r -> takewhile(<(4_000_000), r)
|> r -> Iterators.filter(x -> (x % 2) == 0, r)
|> sum
)
println(result)
|
