Hackerrank Test: Counting programmer string in progxrammerrxproxgrammer, xprogxrmaxemrppprmmograeiruu and programmerprogrammer

programmer-string.rb

class String
  def maulin! n
    slice! n
    self
  end

  def maulin n
    dup.maulin! n
  end
end

def programmerStrings(s)

  programmer = 'programmer'

  head = programmer;

  index = 0

  while(index < s.length) do
    pIndex = head.index(s[index])
    head = head.maulin(pIndex) unless pIndex.nil?
    if head.length == 0
      index += 1
      break
    end
    index += 1
  end

  tail = 'programmer'

  j = s.length - 1

  while(j >= 0) do
    pIndex = tail.index(s[j])
    tail = tail.maulin(pIndex) unless pIndex.nil?
    if tail.length == 0
      j -= 1
      break
    end
    j -= 1
  end

  # puts head
  # puts tail
  # puts index
  # puts j

  return j - index + 1
end


## 'progxrammerrxproxgrammer' => 2
## 'xprogxrmaxemrppprmmograeiruu' => 2
## 'programmerprogrammer' => 0

puts programmerStrings('progxrammerrxproxgrammer')
puts programmerStrings('xprogxrmaxemrppprmmograeiruu')
puts programmerStrings('programmerprogrammer')