Rosetta Code

Lychrel numbers

Check sample numbers for palindrome formation under 200 rounds of the reverse-and-add process, where sums grow far past 64 bits.

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Sourcerosettacode/popular/lychrel_numbers.vibe
def palindrome?(number: int) -> bool
  text = number.to_s
  text == text.reverse
end

def reverse_number(number: int) -> int
  reversed = 0
  current = number
  while current > 0
    reversed = (reversed * 10) + (current % 10)
    current = current // 10
  end
  reversed
end

def lychrel_candidate?(number: int, limit: int) -> bool
  current = number
  iteration = 0

  while iteration < limit
    current = current + reverse_number(current)
    if palindrome?(current)
      return false
    end
    iteration = iteration + 1
  end

  true
end

def run -> array<{ lychrel_candidate: bool, value: int }>
  [
    { value: 56, lychrel_candidate: lychrel_candidate?(56, 200) },
    { value: 57, lychrel_candidate: lychrel_candidate?(57, 200) },
    { value: 196, lychrel_candidate: lychrel_candidate?(196, 200) }
  ]
end

Output

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