linked list w Amy

linked list J

def filter(ll, val)
  fake_ll = Pair.new(424242, ll)

  previous = fake_ll
  while ll != nil
    if ll.a == val
      previous.b = ll.b
    else
      previous = ll
    end
    ll = ll.b
  end

  fake_ll.b
end

def len(ll)
  count = 0
  while ll != nil
    ll = ll.b
    count += 1
  end
  count
end

linked_list.rb

def filter(ll, val)

  while ll.a == val
    return nil if ll.b == nil
    ll = ll.b
  end

  first = ll
  previous = ll
  ll = ll.b

  while ll != nil
    if ll.a == val
      previous.b = ll.b
    else
      previous = ll
    end
    ll = ll.b
  end

  first
end

def len(ll)
  count = 0
  while ll != nil
    ll = ll.b
    count += 1
  end
  count
end

ll = Pair.new(4, Pair.new(4, Pair.new(3, Pair.new(4, nil))))

ll = Pair.new(4, Pair.new(4, nil))

puts len(ll)

ll = filter(ll, 4)

puts len(ll)