Rosetta Code

Palindromic gapful numbers

Find the first palindromic gapful numbers in a bounded decimal range.

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Sourcerosettacode/popular/palindromic_gapful_numbers.vibe
def palindromic_gapful?(number: int) -> bool
  text = number.to_s
  if text.length < 3
    return false
  end

  if text != text.reverse
    return false
  end

  digits = text.chars
  divisor = (digits.fetch(0).to_i * 10) + digits.fetch(-1).to_i
  number % divisor == 0
end

def first_palindromic_gapful_numbers(count: int) -> array<int>
  values: array<int> = []

  outer = 1
  while outer <= 9 && values.length < count
    middle = 0
    while middle <= 9 && values.length < count
      candidate = (outer * 100) + (middle * 10) + outer
      if palindromic_gapful?(candidate)
        values << candidate
      end
      middle = middle + 1
    end
    outer = outer + 1
  end

  outer = 1
  while values.length < count
    inner = 0
    while inner < 100 && values.length < count
      tens = inner // 10
      ones = inner % 10
      candidate = (outer * 1000) + (tens * 100) + (ones * 10) + outer
      if palindromic_gapful?(candidate)
        values << candidate
      end
      inner = inner + 1
    end
    outer = outer + 1
  end

  values
end

def run -> array<int>
  first_palindromic_gapful_numbers(10)
end

Output

Click Run example to see the result.

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