- Added solutions by Peter Meszaros.

- Added solutions by Steven Wilson.
- Added solutions by Matthew Neleigh.
- Added solutions by Laurent Rosenfeld.
- Added solutions by Reinier Maliepaard.

6 files changed, 146 insertions, 0 deletions

diff --git a/challenge-277/laurent-rosenfeld/blog.txt b/challenge-277/laurent-rosenfeld/blog.txt
new file mode 100644
index 0000000000..c5f83d45db
--- /dev/null
+++ b/challenge-277/laurent-rosenfeld/blog.txt
@@ -0,0 +1 @@
+https://blogs.perl.org/users/laurent_r/2024/07/perl-weekly-challenge-277-count-common.html
diff --git a/challenge-277/laurent-rosenfeld/perl/ch-1.pl b/challenge-277/laurent-rosenfeld/perl/ch-1.pl
new file mode 100644
index 0000000000..3c1137e0df
--- /dev/null
+++ b/challenge-277/laurent-rosenfeld/perl/ch-1.pl
@@ -0,0 +1,35 @@
+use warnings;
+use feature 'say';
+use Data::Dumper;
+
+sub count_common {
+    my (%in1, %in2);
+    for my $word (@{$_[0]}) {
+        $in1{$word}++;
+    }
+    for my $word (@{$_[1]}) {
+        $in2{$word}++;
+    }
+    my %unique1 = map { $_ => 1 } grep {$in1{$_} == 1} keys %in1;
+    my %unique2 = map { $_ => 1 } grep {$in2{$_} == 1} keys %in2;
+    my @intersect;
+    for my $word (keys %unique1) {
+        push @intersect, $word if exists $unique2{$word};
+    }
+    return scalar @intersect;
+}
+my @tests = ( [ [<Perl is my friend>],
+               [<Perl and Raku are friend>] ],
+             [ [<Perl is my friend>],
+               [<Raku is friend of my friend Perl>] ],
+             [ [<Perl and Python are very similar>],
+               [<Python is top in guest languages>] ],
+             [ [<Perl is imperative Lisp is functional>],
+               [<Crystal is similar to Ruby>] ]
+           );
+for my $test (@tests) {
+    say  "@{$test->[0]}";
+    say  "@{$test->[1]}";
+    say count_common $test->[0], $test->[1];
+    say "";
+}
diff --git a/challenge-277/laurent-rosenfeld/raku/ch-1.raku b/challenge-277/laurent-rosenfeld/raku/ch-1.raku
new file mode 100644
index 0000000000..32ba7f01f7
--- /dev/null
+++ b/challenge-277/laurent-rosenfeld/raku/ch-1.raku
@@ -0,0 +1,23 @@
+sub count-common (@in1, @in2) {
+    my $bag-in1 = @in1.Bag;
+    my $bag-in2 = @in2.Bag;
+    my $unique1 = grep {$bag-in1{$_} == 1}, $bag-in1.keys;  .
+    my $unique2 = grep {$bag-in2{$_} == 1}, $bag-in2.keys;
+    return ($unique1 ∩ $unique2).elems;
+}
+
+my @tests = ( <Perl is my friend>,
+              <Perl and Raku are friend> ),
+            ( <Perl is my friend>,
+              <Raku is friend of my friend Perl> ),
+            ( <Perl and Python are very similar>,
+              <Python is top in guest languages> ),
+            ( <Perl is imperative Lisp is functional>,
+              <Crystal is similar to Ruby> );
+
+for @tests -> @test {
+    say @test[0];
+    say @test[1];
+    say count-common @test[0], @test[1];
+    say "";
+}
diff --git a/challenge-277/reinier-maliepaard/blog.txt b/challenge-277/reinier-maliepaard/blog.txt
new file mode 100644
index 0000000000..0a4f5cb998
--- /dev/null
+++ b/challenge-277/reinier-maliepaard/blog.txt
@@ -0,0 +1 @@
+https://reiniermaliepaard.nl/perl/pwc/index.php?id=pwc277
diff --git a/challenge-277/reinier-maliepaard/perl/ch-1.pl b/challenge-277/reinier-maliepaard/perl/ch-1.pl
new file mode 100644
index 0000000000..46851c9126
--- /dev/null
+++ b/challenge-277/reinier-maliepaard/perl/ch-1.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+use List::Compare;
+
+sub count_common {
+
+    my ($words1, $words2) = @_;
+
+    # Find common elements using List::Compare
+    my $lc = List::Compare->new($words1, $words2);
+    my @common_words = $lc->get_intersection;
+
+    my %frequency;
+
+    # Count frequencies of common words in both arrays
+    foreach my $word (@common_words) {
+        $frequency{$word}{words1} = scalar ( grep { $_ eq $word } @$words1 );
+        $frequency{$word}{words2} = scalar ( grep { $_ eq $word } @$words2 );
+    }
+
+    # Filter words that appear exactly once in both arrays
+    my @filtered_words = grep { $frequency{$_}{words1} == 1 &&
+                                $frequency{$_}{words2} == 1 } @common_words;
+
+    return(scalar @filtered_words);
+}
+
+# TESTS
+
+my (@words1, @words2);
+
+# Example 1
+@words1 = ("Perl", "is", "my", "friend");
+@words2 = ("Perl", "and", "Raku", "are", "friend");
+print(count_common(\@words1, \@words2), "\n"); # Output: 2
+
+# Example 2
+@words1 = ("Perl", "and", "Python", "are", "very", "similar");
+@words2 = ("Python", "is", "top", "in", "guest", "languages");
+print(count_common(\@words1, \@words2), "\n"); # Output: 1
+
+# Example 3
+@words1 = ("Perl", "is", "imperative", "Lisp", "is", "functional");
+@words2 = ("Crystal", "is", "similar", "to", "Ruby");
+print(count_common(\@words1, \@words2), "\n"); # Output: 0
diff --git a/challenge-277/reinier-maliepaard/perl/ch-2.pl b/challenge-277/reinier-maliepaard/perl/ch-2.pl
new file mode 100644
index 0000000000..34b299344a
--- /dev/null
+++ b/challenge-277/reinier-maliepaard/perl/ch-2.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+use List::Uniq ':all';
+use Math::Combinatorics;
+
+sub strong_pair {
+
+    # Duplicate values are unnecessary and lead to duplicate pairs,
+    # so they should be removed: uniq(@_);
+
+    my $c = Math::Combinatorics->new ( count => 2, data => [uniq(@_)], );
+
+    my $count = 0;
+
+    while ( my @cmb = $c->next_combination ) {
+
+        my $abs = abs($cmb[0] - $cmb[1]);
+        # finding min(): ($x + $y + abs($x - $y)) / 2
+        # https://www.perlmonks.org/?node_id=406883
+        $count++ if ( ($abs < ($cmb[0] + $cmb[1] - $abs) / 2) && ($abs > 0) );
+
+    }
+
+    return ($count);
+}
+
+# TESTS
+
+my @ints;
+
+# Example 1
+@ints = (1, 2, 3, 4, 5);
+print(strong_pair(@ints), "\n"); # Output: 4
+
+# Example 2
+@ints = (5, 7, 1, 7);
+print(strong_pair(@ints), "\n"); # Output: 1