39 lines
609 B
Ruby
39 lines
609 B
Ruby
# @param {Integer} n
|
|
# @return {Integer}
|
|
def fib(n)
|
|
if n == 0 then
|
|
return 0
|
|
end
|
|
|
|
prev, current = 0, 1
|
|
(2..n).each {
|
|
prev, current = current, prev + current
|
|
}
|
|
return current
|
|
end
|
|
|
|
RSpec.describe "fib of " do
|
|
it "0 is 0" do
|
|
expect(fib(0)).to eq(0)
|
|
end
|
|
|
|
it "1 is 1" do
|
|
expect(fib(1)).to eq(1)
|
|
end
|
|
|
|
it "2 is 1" do
|
|
expect(fib(2)).to eq(1)
|
|
end
|
|
|
|
it "3 is 2" do
|
|
expect(fib(3)).to eq(2)
|
|
end
|
|
|
|
it "4 is 3" do
|
|
expect(fib(4)).to eq(3)
|
|
end
|
|
|
|
it "5 is 5" do
|
|
expect(fib(5)).to eq(5)
|
|
end
|
|
end
|