Prev: Send over raw socket?
Next: Web service client help needed
From: Martin DeMello on 14 Jan 2007 14:20
On 1/15/07, Martin DeMello <martindemello(a)gmail.com> wrote:
> n = ARGV[0].to_i
> square = Array.new(n+2) { Array.new(n+2) }

oops - didn't read the question carefully enough. ignore.

m.

From: Matthew Moss on 14 Jan 2007 14:24
My first attempt... A recursive solution recognizing than a spiral of
even dimension can be formed by a top row, a left column, and an odd
spiral. Likewise, an odd spiral is a smaller even spiral with a right
column and bottom row.

The functions erow and orow reflect the even/odd-ness of the spiral,
not the row.



DIM = ARGV[0].to_i
FLD = (DIM ** 2 - 1).to_s.size + 2

def fmt(x)
" " * (FLD - x.to_s.size) + x.to_s
end

def orow(n, i)
m = n ** 2
x = m - n

if i == n - 1
(1..n).inject("") { |o, v| o + fmt(m - v) }
else
erow(n - 1, i) + fmt(x - n + i + 1)
end
end

def erow(n, i)
m = n ** 2
x = m - n

if i == 0
(0...n).inject("") { |o, v| o + fmt(x + v) }
else
fmt(x - i) + orow(n - 1, i - 1)
end
end


def spiral(n)
if (n % 2).zero?
n.times { |i| puts erow(n, i) }
else
n.times { |i| puts orow(n, i) }
end
end

spiral(ARGV[0].to_i)

From: Tom Ayerst on 14 Jan 2007 14:46
My answers assumes an odd numbered spirals (I inferred it from "The
number zero represents the center of the spiral").

Sorry for my beginners ruby (are there some standard min(x,y)/max(x,y,)
functions?)

The approach is to work out a standard equation for the value in any
cell (I ended up with two, for the top left and bottom right) and then
to iterate through each cell and calculate the value. The algorithm is
stateless.

class SpiralMaker
def make_spiral(size)
# only allow odd numbered squares (as zero is centre)
if (size.modulo(2) == 0)
exit(1)
end

#step along row
(1..size).each do |y|
# step down columns
(1..size).each do |x|
# are we in top left or bottom right half of spiral?
if (y+x <= size)
# top left - calculate value
sn = size - (2 * (min(x,y) - 1))
val = (sn*sn) - (3*sn) + 2 - y + x
else
# bottom right - calculate value
sn = size - (2 * (size - max(x,y)))
val = (sn*sn) - sn + y - x
end
# Print value
STDOUT.printf "%03d ", val
end
# Next line
STDOUT.print "\n"
end
end

def min(a,b)
(a <= b) ? a : b
end

def max(a,b)
(a >= b) ? a : b
end
end

maker = SpiralMaker.new
maker.make_spiral 21


From: Simon Kröger on 14 Jan 2007 14:49
Dear Ruby Quiz,

this isn't really a solution to the quiz 109 because it violates
some (if not all) of the rules. But as James noted there was a
code golf problem very similar to this quiz and here is my
solution to that.
(see http://codegolf.com/oblongular-number-spirals for detailed
description of the code golf problem)

----------------------------------------------------------------
s,f=1,proc{|x,y|y<1?[]:[[*s...s+=x]]+f[y-1,x].reverse.transpose}
puts f[w=gets(' ').to_i,gets.to_i].map{|i|['%3i']*w*' '%i}
----------------------------------------------------------------

It draws a number spiral, starting with '1' in the upper left
corner and the highest number in the middle, it also features
spirals that are not quadratic.

Yes, you will get some score at the codegolf site if you repost
this solution there - but nowadays you will only get to Rank 9
with this solution and of course you will start to feel ill and
you won't be able to sleep for days and other nasty things might
happen if you do so.

If someone can derive an even shorter solution from this i would
be very interested to see it (the best ruby solution today has 7
bytes less)

cheers

Simon
From: William James on 14 Jan 2007 17:33

Simon Kröger wrote:
> Dear Ruby Quiz,
>
> this isn't really a solution to the quiz 109 because it violates
> some (if not all) of the rules. But as James noted there was a
> code golf problem very similar to this quiz and here is my
> solution to that.
> (see http://codegolf.com/oblongular-number-spirals for detailed
> description of the code golf problem)
>
> ----------------------------------------------------------------
> s,f=1,proc{|x,y|y<1?[]:[[*s...s+=x]]+f[y-1,x].reverse.transpose}
> puts f[w=gets(' ').to_i,gets.to_i].map{|i|['%3i']*w*' '%i}
> ----------------------------------------------------------------
>
> It draws a number spiral, starting with '1' in the upper left
> corner and the highest number in the middle, it also features
> spirals that are not quadratic.
>
> Yes, you will get some score at the codegolf site if you repost
> this solution there - but nowadays you will only get to Rank 9
> with this solution and of course you will start to feel ill and
> you won't be able to sleep for days and other nasty things might
> happen if you do so.
>
> If someone can derive an even shorter solution from this i would
> be very interested to see it (the best ruby solution today has 7
> bytes less)
>
> cheers
>
> Simon

I can't get this to work.

E:\Ruby>ruby try.rb
4 4
try.rb:2:in `%': too few arguments. (ArgumentError)
from try.rb:2
from try.rb:2:in `map'
from try.rb:2

First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4 5 6
Prev: Send over raw socket?
Next: Web service client help needed