056_powerful_digit_sum.rb

# A googol (10100) is a massive number: one followed by one-hundred zeros; 100100 is almost unimaginably large: one followed by two-hundred zeros. Despite their size, the sum of the digits in each number is only 1.

# Considering natural numbers of the form, ab, where a, b < 100, what is the maximum digital sum?

def digit_sum(number)
	sum = 0
	number.to_s.each_char do |digit|
		sum += digit.to_i
	end
	sum
end

a = 1
maximum_digit_sum = 1

while a < 100
	b = 1
	while b < 100
		c = a**b
		if digit_sum(c) > maximum_digit_sum
			maximum_digit_sum = digit_sum(c)
		end
		b += 1
	end
	a += 1
end

puts maximum_digit_sum