feat(challenge-249/lubos-kolouch/perl,python,raku,blog): Challenge 249 LK Perl Python Raku blog

7 files changed, 186 insertions, 0 deletions

diff --git a/challenge-249/lubos-kolouch/blog.txt b/challenge-249/lubos-kolouch/blog.txt
new file mode 100644
index 0000000000..8dcbaf2e9f
--- /dev/null
+++ b/challenge-249/lubos-kolouch/blog.txt
@@ -0,0 +1 @@
+https://egroup.kolouch.org/nextcloud/sites/lubos/2023-12-25_Weekly_challenge_249
diff --git a/challenge-249/lubos-kolouch/perl/ch-1.pl b/challenge-249/lubos-kolouch/perl/ch-1.pl
new file mode 100644
index 0000000000..26010b0066
--- /dev/null
+++ b/challenge-249/lubos-kolouch/perl/ch-1.pl
@@ -0,0 +1,42 @@
+use strict;
+use warnings;
+use Test::More;
+
+sub equal_pairs {
+    my @ints = @_;
+    my %freq;
+    my @order;
+
+    # Count the frequency of each element and track the order
+    foreach my $int (@ints) {
+        if ( !exists $freq{$int} ) {
+            push @order, $int;
+        }
+        $freq{$int}++;
+    }
+
+    # Check if all elements have even frequency
+    foreach my $key ( keys %freq ) {
+        return [] if $freq{$key} % 2;    # Returning an array reference
+    }
+
+    # Form pairs
+    my @pairs;
+    foreach my $key (@order) {
+        push @pairs, ( [ $key, $key ] ) x ( $freq{$key} / 2 );
+    }
+
+    return \@pairs;
+}
+
+# Test cases
+subtest 'Test Cases' => sub {
+    is_deeply(
+        equal_pairs( 3, 2, 3, 2, 2, 2 ),
+        [ [ 3, 3 ], [ 2, 2 ], [ 2, 2 ] ],
+        'Example 1'
+    );
+    is_deeply( equal_pairs( 1, 2, 3, 4 ), [], 'Example 2' ); # Revised test case
+};
+
+done_testing();
diff --git a/challenge-249/lubos-kolouch/perl/ch-2.pl b/challenge-249/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..9be18e7f07
--- /dev/null
+++ b/challenge-249/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,27 @@
+use strict;
+use warnings;
+use Test::More tests => 3;
+
+sub di_string_match {
+    my ($str) = @_;
+    my $n = length($str);
+    my ( $low, $high ) = ( 0, $n );
+    my @perm = ();
+
+    foreach my $char ( split //, $str ) {
+        if ( $char eq 'I' ) {
+            push @perm, $low++;
+        }
+        else {
+            push @perm, $high--;
+        }
+    }
+
+    push @perm, $low;    # $low == $high at this point
+    return @perm;
+}
+
+# Tests
+is_deeply( [ di_string_match("IDID") ], [ 0, 4, 1, 3, 2 ], 'Test IDID' );
+is_deeply( [ di_string_match("III") ],  [ 0, 1, 2, 3 ], 'Test III' );
+is_deeply( [ di_string_match("DDI") ],  [ 3, 2, 0, 1 ], 'Test DDI' );
diff --git a/challenge-249/lubos-kolouch/python/ch-1.py b/challenge-249/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..286bd201e4
--- /dev/null
+++ b/challenge-249/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,38 @@
+import unittest
+from collections import Counter
+
+
+def equal_pairs(ints):
+    freq = Counter(ints)
+    seen = set()
+    ordered_elements = []
+
+    # Keep the order of first occurrence
+    for num in ints:
+        if num not in seen:
+            seen.add(num)
+            ordered_elements.append(num)
+
+    # Check if all elements have even frequency
+    if any(count % 2 for count in freq.values()):
+        return []
+
+    # Form pairs in the order of first occurrence
+    pairs = []
+    for num in ordered_elements:
+        pairs.extend([[num, num] for _ in range(freq[num] // 2)])
+
+    return pairs
+
+
+# Unit tests
+class TestEqualPairs(unittest.TestCase):
+    def test_example_1(self):
+        self.assertEqual(equal_pairs([3, 2, 3, 2, 2, 2]), [[3, 3], [2, 2], [2, 2]])
+
+    def test_example_2(self):
+        self.assertEqual(equal_pairs([1, 2, 3, 4]), [])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/challenge-249/lubos-kolouch/python/ch-2.py b/challenge-249/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..723490c7bb
--- /dev/null
+++ b/challenge-249/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+
+import unittest
+from typing import List
+
+
+def di_string_match(s: str) -> list[int]:
+    low, high = 0, len(s)
+    perm = []
+
+    for char in s:
+        if char == "I":
+            perm.append(low)
+            low += 1
+        else:
+            perm.append(high)
+            high -= 1
+
+    perm.append(low)  # low == high at this point
+    return perm
+
+
+# Tests
+
+
+class TestDIStringMatch(unittest.TestCase):
+    def test_cases(self):
+        self.assertEqual(di_string_match("IDID"), [0, 4, 1, 3, 2])
+        self.assertEqual(di_string_match("III"), [0, 1, 2, 3])
+        self.assertEqual(di_string_match("DDI"), [3, 2, 0, 1])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/challenge-249/lubos-kolouch/raku/ch-1.raku b/challenge-249/lubos-kolouch/raku/ch-1.raku
new file mode 100644
index 0000000000..d59a8937e2
--- /dev/null
+++ b/challenge-249/lubos-kolouch/raku/ch-1.raku
@@ -0,0 +1,23 @@
+use Test;
+
+sub equal-pairs(@ints) {
+    my %freq = @ints.Bag;
+
+    # Check if all elements have even frequency
+    return [] if %freq.values.any(* % 2);
+
+    # Form pairs
+    my @pairs;
+    for %freq.kv -> $num, $count {
+        @pairs.append([$num, $num]) for 1..($count div 2);
+    }
+
+    return @pairs;
+}
+
+# Tests
+plan 2;
+is-deeply equal-pairs(3, 2, 3, 2, 2, 2), [[2, 2], [2, 2], [3, 3]], 'Example 1';
+is-deeply equal-pairs(1, 2, 3, 4), [], 'Example 2';
+
+done-testing;
diff --git a/challenge-249/lubos-kolouch/raku/ch-2.raku b/challenge-249/lubos-kolouch/raku/ch-2.raku
new file mode 100644
index 0000000000..8c06d0eb48
--- /dev/null
+++ b/challenge-249/lubos-kolouch/raku/ch-2.raku
@@ -0,0 +1,21 @@
+use Test;
+
+sub di-string-match(Str $str) {
+    my $n = $str.chars;
+    my ($low, $high) = 0, $n;
+    my @perm;
+
+    for $str.comb -> $char {
+        @perm.push($char eq 'I' ?? $low++ !! $high--);
+    }
+
+    @perm.push($low);  # $low == $high at this point
+    return @perm;
+}
+
+# Tests
+is-deeply di-string-match("IDID"), [0, 4, 1, 3, 2], 'Test IDID';
+is-deeply di-string-match("III"), [0, 1, 2, 3], 'Test III';
+is-deeply di-string-match("DDI"), [3, 2, 0, 1], 'Test DDI';
+
+done-testing;