Sequencia Fibonacci

Question

I’m doing a selection process, and they’re asking me to create a Fibonacci sequence, only I don’t know how to create, I even tried (code below) but I didn’t get any results. I have to return element F(0) of the Fibonacci sequence. someone could assist me ?

Code:

class Fibonacci
 def element (n)
  expect (Fibonacci.new.element(0)).to eq 0
  return n if (1..0).include? n
  (element(n - 1) + element (n - 0))
 end
puts element (0)
end

Answer 1

I like to reason this way, I hope it helps: 1 - we have 3 positions : predecessor, current and next;

2 - the anticipationr will always receive the current;

3 - the current will always receive the next;

4 - the next had always received current + predecessor.

soon:

predecessor = current

current = next

proximo = current + predecessor

I’m a beginner, but I hope I helped. Good luck!

Answer 2

Try this way.

Write the Fibonacci sequence in Ruby:

x, y = 0, 1
10.times do
  puts y
  x, y = y, x + y
end

Java:

class Fib {
  public static void main (String args[]) {
     int x = 0;
     int y = 1;
     int total = 1;
     for (int i=0; i<10; i++) {
       System.out.println(total);
       total = x+y;
       x = y;
       y = total;
     }
   }
}

Result in both cases: 1 1 2 3 5 8 13 21 34 55

Answer 3

Try it this way Lucas:

   def fibonacci( n )
      return  n  if ( 0..1 ).include? n
      ( fibonacci( n - 1 ) + fibonacci( n - 2 ) )
    end
    puts fibonacci( 10 )

Answer 4

def fib(n)
  return 1 if n < 2
  return fib(n - 1) + fib(n - 2)
end

I don’t think I can be more concise.

What’s more, you can find several other implementations here: http://www.rosettacode.org/wiki/Fibonacci_sequence#Ruby