mirror of
https://github.com/TheAlgorithms/Ruby
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27 lines
617 B
Ruby
27 lines
617 B
Ruby
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# frozen_string_literal: true
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# A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.
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# Find the largest palindrome made from the product of two 3-digit numbers.
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class Integer
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def parindrome?
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self == reverse
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end
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# 123.reverse == 321
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# 100.reverse == 1
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def reverse
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result = 0
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n = self
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loop do
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result = result * 10 + n % 10
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break if (n /= 10).zero?
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end
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result
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end
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end
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factors = (100..999).to_a
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products = factors.product(factors).map { _1 * _2 }
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puts products.select(&:parindrome?).max
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