Project Euler Problem 38

問題

Take the number 192 and multiply it by each of 1, 2, and 3:

    192 × 1 = 192
    192 × 2 = 384
    192 × 3 = 576

By concatenating each product we get the 1 to 9 pandigital, 192384576. We will call
192384576 the concatenated product of 192 and (1,2,3)

The same can be achieved by starting with 9 and multiplying by 1, 2, 3, 4, and 5,
giving the pandigital, 918273645, which is the concatenated product of 9 and (1,2,3,4,5).

What is the largest 1 to 9 pandigital 9-digit number that can be formed as the
concatenated product of an integer with (1,2, ... , n) where n > 1?

ソース

pandigital = []
(1...10000).each{|i|
	(2..9).each{|j|
		str = (1..j).inject(""){|s, x|
			s += (i * x).to_s
		}
		pandigital << str.to_i if str.size == 9 && str.to_s.scan(/./).sort.join == "123456789"
		break if str.size >= 9
	}
}
puts pandigital.max

解答

932718654

感想

まだまだ簡単！いけるぞ〜