add 1k method

1 files changed, 48 insertions, 2 deletions

diff --git a/challenge-153/james-smith/perl/ch-2.pl b/challenge-153/james-smith/perl/ch-2.pl
index 457b3cbd80..b04809c552 100644
--- a/challenge-153/james-smith/perl/ch-2.pl
+++ b/challenge-153/james-smith/perl/ch-2.pl
@@ -8,13 +8,25 @@ use Test::More;
 use Benchmark qw(cmpthese timethis);
 use Data::Dumper qw(Dumper);
 
+## Prep for tests!
 my @f = (1);
 push @f, $_*$f[-1] foreach 1..9;
+my @t = map { my $t = $_; map {$t+$_} @f } @f;
+my @q = map { my $t = $_; map {$t+$_} @f } @t;
 
 my @TESTS = ( [ 145, 1 ], [ 125, 0 ], );
-is( is_factorion($_->[0])||0, $_->[1] ) foreach @TESTS;
+is( is_factorion(    $_->[0])||0, $_->[1] ) foreach @TESTS;
+is( is_factorion_1k( $_->[0])||0, $_->[1] ) foreach @TESTS;
 done_testing();
 
+say join ', ', get_factorions();
+say join ', ', get_factorions_1k();
+
+cmpthese( 100, {
+  '10' => sub { get_factorions()    },
+  '1k' => sub { get_factorions_1k() },
+});
+
 ## Has to be at most 7 digits as 8x9! < 9_999_999
 ## We note that 8x9^7 is the maximum possible value
 ## Further the value of this is 2_540_160. So we note
@@ -23,7 +35,18 @@ done_testing();
 ## So we are guaranteed to find all values if we
 ## search as far as this value...
 
-is_factorion($_) && say for 1 .. 2_177_282;
+## In the 1k method - we cheat and store the sum of 3 factorials for values
+## from 0..999 {along with 2 digit version 0..99 and the previously used 0..9}
+## We have to do this as the sum of "99" isn't the same as the sum "099".
+
+sub get_factorions {
+  @f = (1);
+  push @f, $_*$f[-1] foreach 1..9;
+
+  my @res;
+  is_factorion($_) && push @res,$_ for 1 .. 2_177_282;
+  return @res;
+}
 
 sub is_factorion {
   my $t = $_[0];
@@ -31,3 +54,26 @@ sub is_factorion {
   return 0;
 }
 
+sub get_factorions_1k {
+  @f = (1);
+  push @f, $_*$f[-1] foreach 1..9;
+  @t = map { my $t = $_; map {$t+$_} @f } @f;
+  @q = map { my $t = $_; map {$t+$_} @f } @t;
+  my @res;
+  is_factorion_1k($_) && push @res,$_ for 1 .. 2_177_282;
+  return @res;
+}
+
+sub is_factorion_1k {
+  my $t = $_[0];
+  return $t == (
+      $t >= 1e6 ? $f[ $t/1e6 ] + $q[ ($t/1e3)%1e3 ] + $q[ $t%1e3 ]
+    : $t >= 1e5 ? $q[ $t/1e3 ] + $q[ $t%1e3 ]
+    : $t >= 1e4 ? $t[ $t/1e3 ] + $q[ $t%1e3 ]
+    : $t >= 1e3 ? $f[ $t/1e3 ] + $q[ $t%1e3 ]
+    : $t >= 100 ? $q[ $t ]
+    : $t >=  10 ? $t[ $t ]
+    :             $f[ $t ]
+  );
+}
+