DAJ #252

3 files changed, 87 insertions, 0 deletions

diff --git a/challenge-252/dave-jacoby/blog.txt b/challenge-252/dave-jacoby/blog.txt
new file mode 100644
index 0000000000..042018a7eb
--- /dev/null
+++ b/challenge-252/dave-jacoby/blog.txt
@@ -0,0 +1 @@
+https://jacoby.github.io/2024/01/15/camelia-goes-to-monte-carlo-weekly-challenge-252.html
diff --git a/challenge-252/dave-jacoby/perl/ch-1.pl b/challenge-252/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..f1b874189f
--- /dev/null
+++ b/challenge-252/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ say postderef signatures state };
+
+use List::Util qw{ sum0 };
+
+my @examples = (
+
+    [ 1, 2, 3, 4 ],
+    [ 2, 7, 1, 19, 18, 3 ],
+);
+
+for my $example (@examples) {
+    my $input  = join ', ', $example->@*;
+    my $output = special_numbers( $example->@* );
+
+    say <<~"END";
+    Input:  \$ints = ($input)
+    Output: $output
+    END
+}
+
+sub special_numbers (@input) {
+    my $output = 0;
+    my $n      = scalar @input;
+    return 
+        sum0 
+        map { $input[ $_ - 1 ] ** 2 } 
+        grep { $n % $_ == 0 } 
+        1 .. scalar @input;
+
+    ## the longer form I wrote first
+    # for my $i ( 1 .. scalar @input ) {
+    #     if ( $n % $i == 0 ) {
+    #         my $v = $input[ $i - 1 ];
+    #         $output += ( $v**2 );
+    #     }
+    # }
+    # return $output;
+}
diff --git a/challenge-252/dave-jacoby/perl/ch-2.pl b/challenge-252/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..18f840974b
--- /dev/null
+++ b/challenge-252/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,44 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ say postderef signatures state };
+
+use List::Util qw{ sum0 };
+use JSON;
+my $j = JSON->new->pretty;
+
+my @examples = ( 1, 3, 4, 5, 7 );
+for my $input (@examples) {
+    my $o      = unique_sum_zero($input);
+    my $output = join ', ', $o->@*;
+
+    say <<~"END";
+    Input:  \$matrix = $input
+    Output: ($output)
+    END
+}
+
+sub unique_sum_zero ( $input, $list = [] ) {
+    return [0] if $input == 1;             # handle zero case
+    if ( $input == scalar $list->@* ) {    # control recursion
+        return $list if 0 == sum0 $list->@*;
+        return -1;
+    }
+    my $c = 0;
+    while (1) {
+        my @list = $list->@*;
+        my $n = -9 + int rand 19;           # generates a number between -9 and 9
+        next if grep { $_ == $n } @list;    # removes duplicates
+        push @list, $n;
+        my $return = unique_sum_zero( $input, \@list );
+        if ( ref $return && ref $return eq 'ARRAY' ) {
+            return $return;
+        }
+
+        # if you have bad numbers, it'll be hard to recover
+        # so we'll give up after a while
+        return -1 if $c++ > 100;
+    }
+    return -1;
+}