Please Forward: Ruby Quiz Submission

ruby-talk
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From: "Mark Harris" <mdh103@soton.ac.uk>
Date: January 16, 2007 2:06:47 PM CST
To: submission@rubyquiz.com
Subject: Please Forward: Ruby Quiz Submission

Hi

My first submission, not been using Ruby that long and come from a couple of years learning Java at Uni, which probably shows.
Thanks for running and hosting the quizzes, trawling through the archive was very informative.

Mark Harris

class NumberSpiral

include Enumerable

def initialize(dimension)
@n = dimension
@even = dimension % 2
@maxSize = (@n**2 - 1).to_s.length
end

def each
@line=0
(0..@n-1).map { yield nextLine }
@line=0
end

private

def nextLine
result = spiral(@n, @line)
@line+=1
result.map{ |x| x.to_s.center(@maxSize) }.join(" ")
end

def spiral(n, l)
if (n==1)
0
elsif (n % 2 ==0)
#Even
if (l == 0)
# Top row, just return it.
(n**2 - n)..(n**2-1)
else
# Same as the square of size (n-1) at line (l-1) with this square's number in front.
([(n**2 - n - l)] << spiral(n-1,l-1)).flatten
end
else
#Odd
if (l==(n-1))
# Bottom row, just return it
a = Array.new
(n**2-1).downto(n**2-n) { |x| a << x}
a
else
#Same as the square of size (n-1) at line l with this square's number at the end.
(spiral(n-1,l).to_a << [(n ** 2 - 2*n + 1 + l)]).flatten
end

spiral = NumberSpiral.new((ARGV[0] || 9).to_i)
spiral.each {|x| puts x }

ยทยทยท

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