Euler Project Problem #045

euler45.rb

# Solution to Project Euler's forty-fifth problem
# http://projecteuler.net/index.php?section=problems&id=45
# Find the second number which is a triangle number, pentagonal number, and hexagonal number.
def create_pentagonal_number(number)
	pentagonal = (number*(3*number-1))/2
	return pentagonal
end
def create_hexagonal_number(number)
	hexagonal = number*(2*number-1)
	return hexagonal
end
def compare_hex_and_pent_numbers(one, two)
	pent = create_pentagonal_number(one)
	hex = create_hexagonal_number(two)
	compare = 2
	until compare == 0
		compare = pent <=> hex
		case compare
			when 0
				p pent
			when -
				one += 1
				pent = create_pentagonal_number(one)
			when 1
				two += 1
				hex = create_hexagonal_number(two)
		end
	end
end

a = Time.new
pent_count = 166
hex_count = 144
compare_hex_and_pent_numbers(pent_count, hex_count)
b = Time.new - a
p b