Merge pull request #12868 from rjt-pl/master

rjt's week 343 solutions and blog

7 files changed, 113 insertions, 4 deletions

diff --git a/challenge-343/ryan-thompson/README.md b/challenge-343/ryan-thompson/README.md
index ec7aeb0f5f..2d781de9ed 100644
--- a/challenge-343/ryan-thompson/README.md
+++ b/challenge-343/ryan-thompson/README.md
@@ -1,18 +1,18 @@
 # Ryan Thompson
 
-## Week 342 Solutions
+## Week 343 Solutions
 
-### Task 1 › Balanced Strings
+### Task 1 › Zero Friend
 
  * [Perl](perl/ch-1.pl)
 
-### Task 2 › Max Score
+### Task 2 › Champion Team
 
  * [Perl](perl/ch-2.pl)
 
 ## Blog
 
- * [Perfectly Balanced and Pointlessly Optimized](https://ry.ca/2025/10/pwc-342-balanced-optimized/)
+ * [It's hard to make friends when you're a zero](https://ry.ca/2025/10/pwc-343-its-hard-to-make-friends/)
 
 ## Tests
 
diff --git a/challenge-343/ryan-thompson/blog.txt b/challenge-343/ryan-thompson/blog.txt
new file mode 100644
index 0000000000..3dad97d295
--- /dev/null
+++ b/challenge-343/ryan-thompson/blog.txt
@@ -0,0 +1 @@
+https://ry.ca/2025/10/pwc-343-its-hard-to-make-friends/
diff --git a/challenge-343/ryan-thompson/perl/ch-1.pl b/challenge-343/ryan-thompson/perl/ch-1.pl
new file mode 100644
index 0000000000..f41f26fd09
--- /dev/null
+++ b/challenge-343/ryan-thompson/perl/ch-1.pl
@@ -0,0 +1,6 @@
+#!/usr/bin/env perl
+
+use v5.38;
+use List::Util qw< min >;
+
+sub zero_friend { min map abs, @_ }
diff --git a/challenge-343/ryan-thompson/perl/ch-2.pl b/challenge-343/ryan-thompson/perl/ch-2.pl
new file mode 100644
index 0000000000..bb72c3008e
--- /dev/null
+++ b/challenge-343/ryan-thompson/perl/ch-2.pl
@@ -0,0 +1,10 @@
+#!/usr/bin/env perl
+
+use v5.38;
+use List::Util qw< sum max reduce >;
+
+sub best {
+    my ($bs,$bi,$s) = (0,0);
+    ($s = sum $_[$_]->@*) > $bs and ($bs,$bi)=($s,$_) for 0..$#_;
+    $bi;
+}
diff --git a/challenge-343/ryan-thompson/perl/ch-2a.pl b/challenge-343/ryan-thompson/perl/ch-2a.pl
new file mode 100644
index 0000000000..b1ed5b2d77
--- /dev/null
+++ b/challenge-343/ryan-thompson/perl/ch-2a.pl
@@ -0,0 +1,51 @@
+#!/usr/bin/env perl
+#
+# ch-2a.pl - Alternate solutions (see blog)
+
+use v5.38;
+use List::Util qw< sum max reduce >;
+
+sub reduce1 {
+    (reduce { $a->[1] > $b->[1] ? $a : $b }
+        map { [   $_ => sum @{$_[$_]}   ] } keys @_)->[0];
+}
+
+sub reduce2 {
+    my @teams = map { sum @$_ } @_;
+    reduce { $teams[$a] > $teams[$b] ? $a : $b } keys @_;
+}
+
+sub hash_ {
+    my %vals = map { sum(@{$_[$_]}) => $_ } keys @_;
+    $vals{ max keys %vals }
+}
+
+sub loop {
+    my @best = (0,0);
+    for (keys @_) {
+        my $sum = sum $_[$_]->@*;
+        @best = ($sum, $_) if $sum > $best[0];
+    }
+    $best[1];
+}
+
+
+# Benchmark them if --bench is given
+if ($ARGV[0] and $ARGV[0] =~ /^--bench(mark)?$/) {
+    require './ch-2.pl';
+    use Benchmark qw< cmpthese >;
+
+    my @grid = ([0,0,0,0,0],
+                [1,0,0,0,0],
+                [1,1,0,1,1],
+                [1,1,0,0,0],
+                [1,1,0,1,0]);
+
+    cmpthese(-3, {
+        reduce1 => sub { reduce1(@grid) },
+        reduce2 => sub { reduce2(@grid) },
+        hash    => sub { hash_(@grid) },
+        loop    => sub { loop(@grid) },
+        best    => sub { best(@grid) },
+    });
+}
diff --git a/challenge-343/ryan-thompson/perl/t/ch-1.t b/challenge-343/ryan-thompson/perl/t/ch-1.t
new file mode 100644
index 0000000000..ea3212b47f
--- /dev/null
+++ b/challenge-343/ryan-thompson/perl/t/ch-1.t
@@ -0,0 +1,12 @@
+use Test2::V0;
+
+require './ch-1.pl';
+
+is zero_friend(4,2,-1,3,-2),    1;
+is zero_friend(-5,5,-3,3,-1,1), 1;
+is zero_friend(7,-3,0,2,8),     0;
+is zero_friend(-2,-5,-1,-8),    1;
+is zero_friend(-2,2,-4,4,-1,1), 1;
+is zero_friend(2,-2,4,-4,1,-1), 1;
+
+done_testing;
diff --git a/challenge-343/ryan-thompson/perl/t/ch-2.t b/challenge-343/ryan-thompson/perl/t/ch-2.t
new file mode 100644
index 0000000000..1be8d09383
--- /dev/null
+++ b/challenge-343/ryan-thompson/perl/t/ch-2.t
@@ -0,0 +1,29 @@
+use Test2::V0;
+
+require './ch-2.pl';
+
+is best([0, 1, 1],
+        [0, 0, 1],
+        [0, 0, 0]),         0;
+
+is best([0, 1, 0, 0],
+        [0, 0, 0, 0],
+        [1, 1, 0, 0],
+        [1, 1, 1, 0]),      3;
+
+is best([0, 1, 0, 1],
+        [0, 0, 1, 1],
+        [1, 0, 0, 0],
+        [0, 0, 1, 0]),      0;
+
+is best([0, 1, 1],
+        [0, 0, 0],
+        [0, 1, 0]),         0;
+
+is best([0, 0, 0, 0, 0],
+        [1, 0, 0, 0, 0],
+        [1, 1, 0, 1, 1],
+        [1, 1, 0, 0, 0],
+        [1, 1, 0, 1, 0]),   2;
+
+done_testing;