Solution 6: Almost Palindrome

A palindrome is a series of characters which is the same spelled forward and in reverse. For the purpose of this exercise, a capital letter is equal to its lowercase equivalent. Given a string, return whether or not the string would be a palindrome if one or fewer characters were removed. Return true if it is a palindrome or almost a palindrome, and false otherwise.

def palindrome(string)
  return true if string == string.reverse

  valid = true
  one_off = false
  looping = true
  first = 0
  last = string.length - 1
  
  while looping
    break if first > last

    if string[first] == string[last]
      first = first + 1
      last = last - 1
      looping = false if first == last || first > last
      next
    end

    if one_off
      valid = false
      break
    end

    if string[first+1] == string[last]
      one_off = true
      first = first + 2
      last = last - 1
      looping = false if first == last
      next
    end

    if string[first] == string[last-1]
      one_off = true
      first = first + 1
      last = last - 2
      looping = false if first == last
      next
    end

    valid = false
    break
  end
  
  valid
end