August 28, 2019
#!raku
# Given a matrix of m x n elements (m rows, n columns),
# return all elements of the matrix in spiral order.
#
# Example 1:
# Input:
# [[ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ]]
# Output:
# [1, 2, 3, 6, 9, 8, 7, 4, 5]
#
# Example 2:
# Input:
# [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
# Output:
# [1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7]
enum Dir ;
class Cur {
has Int $.row is rw = 0;
has Int $.col is rw = 0;
has Dir $.dir is rw = Dir::Right;
has $!d = ((0, 1), (1, 0), (0, -1), (-1, 0));
method next {
$.dir = self.next-dir($.dir);
$.row += $!d[$.dir][0];
$.col += $!d[$.dir][1];
}
method same-dir(:@a, --> Bool) {
if @a[$.row + $!d[$.dir][0]][$.col + $!d[$.dir][1]] {
$.row += $!d[$.dir][0];
$.col += $!d[$.dir][1];
True;
} else {
False;
}
}
method next-dir(Dir $dir) {
given $dir {
when Dir::Right { Dir::Down }
when Dir::Down { Dir::Left }
when Dir::Left { Dir::Up }
when Dir::Up { Dir::Right }
}
}
}
class Spiral {
has @!a;
has @.b of Int is rw;
has Cur $!c;
submethod BUILD(:@!a) {
$!c = Cur.new;
my $e = @!a.flatmap(|*).elems;
while @!b.elems != $e {
if @!a[$!c.row][$!c.col] {
@!b.push(@!a[$!c.row][$!c.col]);
@!a[$!c.row][$!c.col] = 0;
$!c.next unless $!c.same-dir(:@!a);
} else {
$!c.next;
}
}
}
}
use Test;
my @a = (1..9).Array.rotor(3);
ok Spiral.new(:@a).b == [1, 2, 3, 6, 9, 8, 7, 4, 5];
@a = (1..12).Array.rotor(3);
ok Spiral.new(:@a).b == [1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7];
raku (17) matrix (1)
