Here's some code for finding paths of a given length starting from a given spot. You just need to run through all the starting spots and find the paths of the desired lengths. There will be a lot of them.
my %adjacency_list = (
1 => [2,5,6],
2 => [1,3,5,6,7],
3 => [2,4,6,7,8],
4 => [3,7,8],
5 => [1,2,6,9,10],
6 => [1,2,3,5,7,9,10,11],
7 => [2,3,4,6,8,10,11,12],
8 => [3,4,7,11,12],
9 => [5,6,10,13,14],
10 => [5,6,7,9,11,13,14,15],
11 => [6,7,8,10,12,14,15,16],
12 => [7,8,11,15,16],
13 => [9,10,14],
14 => [9,10,11,13,15],
15 => [10,11,12,14,16],
16 => [11,12,15]
);
sub find_path {
my ($start_at, $length, $been_there) = (@_, {});
if ($length <= 1) {
return [$start_at];
}
else {
my @try_these = grep { ! $been_there->{$_} } @{$adjacency_list{$st
+art_at}};
return map {
my @cdr_list = find_path($_, $length-1, {%$been_there, $start_at
+ => 1});
map [$start_at, @$_], @cdr_list;
} @try_these;
}
}
# Example usage:
print "@$_\n" for (find_path(3, 3));
Caution: Contents may have been coded under pressure.