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#!/usr/bin/perl -w
# Copyright 2010, 2011, 2012 Kevin Ryde
# This file is part of Math-PlanePath.
#
# Math-PlanePath is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 3, or (at your option) any later
# version.
#
# Math-PlanePath is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with Math-PlanePath. If not, see <http://www.gnu.org/licenses/>.
# Usage: perl square-numbers.pl
#
# Print the SquareSpiral numbers in a grid like
#
# 37 36 35 34 33 32 31
# 38 17 16 15 14 13 30
# 39 18 5 4 3 12 29
# 40 19 6 1 2 11 28
# 41 20 7 8 9 10 27
# 42 21 22 23 24 25 26
# 43 44 45 46 47 ...
#
# See numbers.pl for a more sophisticated program.
use 5.004;
use strict;
use List::Util 'min', 'max';
use Math::PlanePath::SquareSpiral;
my $n_max = 115;
my $path = Math::PlanePath::SquareSpiral->new;
my %rows;
my $x_min = 0;
my $x_max = 0;
my $y_min = 0;
my $y_max = 0;
foreach my $n ($path->n_start .. $n_max) {
my ($x, $y) = $path->n_to_xy ($n);
$rows{$x}{$y} = $n;
$x_min = min($x_min, $x);
$x_max = max($x_max, $x);
$y_min = min($y_min, $y);
$y_max = max($y_max, $y);
}
my $cellwidth = length($n_max) + 2;
foreach my $y (reverse $y_min .. $y_max) {
foreach my $x ($x_min .. $x_max) {
printf ('%*s', $cellwidth, $rows{$x}{$y} || '');
}
print "\n";
}
exit 0;
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