Insanely large profile

gistfile1.txt

# Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
# real	0m2.053s
# user	0m1.960s
# sys	  0m0.052s
# This is Rakudo version 2016.03-39-gf220a5e built on MoarVM version 2016.03-46-g50c7f6a
use v6;
my $num = '73167176531330624919225119674426574742355349194934' ~
'96983520312774506326239578318016984801869478851843' ~
'85861560789112949495459501737958331952853208805511' ~
'12540698747158523863050715693290963295227443043557' ~
'66896648950445244523161731856403098711121722383113' ~
'62229893423380308135336276614282806444486645238749' ~
'30358907296290491560440772390713810515859307960866' ~
'70172427121883998797908792274921901699720888093776' ~
'65727333001053367881220235421809751254540594752243' ~
'52584907711670556013604839586446706324415722155397' ~
'53697817977846174064955149290862569321978468622482' ~
'83972241375657056057490261407972968652414535100474' ~
'82166370484403199890008895243450658541227588666881' ~
'16427171479924442928230863465674813919123162824586' ~
'17866458359124566529476545682848912883142607690042' ~
'24219022671055626321111109370544217506941658960408' ~
'07198403850962455444362981230987879927244284909188' ~
'84580156166097919133875499200524063689912560717606' ~
'05886116467109405077541002256983155200055935729725' ~
'71636269561882670428252483600823257530420752963450';

my $windowSize = 13;
my $res = 0;
my $product = 1;
loop (my $i = 0; $i <= $num.chars - $windowSize; $i++) {
  my @factors = $num.substr($i, $windowSize).comb;
  my $tmpProd = [*] @factors;
  if $tmpProd > $product {
    $product = $tmpProd;
    $res = $num.substr($i, $windowSize);
  }
}
say "Adj. $res gives product $product";