Fibonacci with Dynamic Programming

fibonacci.rb

def fib(n)
  cache = {}

  n.times do |i|
    if i == 0
      cache[0] = 0
    elsif i == 1
      cache[1] = 1
    else
      cache[i] = cache[i-1] + cache[i-2]
    end
  end

  return cache[n-1]
end

puts "11: #{fib(11)}"