The Weekly Challenge: 376

TABLE OF CONTENTS

  1. HEADLINES

  2. SPONSOR

  3. RECAP

  4. PERL REVIEW

  5. RAKU REVIEW

  6. CHART

  7. NEW MEMBERS

  8. GUESTS

  9. TASK #1: Chessboard Squares

10. TASK #2: Doubled Words

HEADLINES

Welcome to the Week #376 of The Weekly Challenge.

Today is the first Monday of the month, which means it is time to declare the Champion of the Month. It is with great pleasure that I announce David Smith as our next champion. As of today, he has contributed 30 solutions in Raku language.

I was eagerly waiting for the sun to arrive, but now that it’s here in full force, I am fighting hay fever. The silver lining is that I have been spending most of my time indoors, which has given me the chance to work on my TODO list. I have been writing about my experiments in a blog post, which you can find here. Since I have started blogging, I might begin writing about my contributions as well. I don’t want to rush though, I’d rather take my time than burn out too quickly.

Below is my contributions to the Task #1 of Week #375.

Perl: source code

sub count_unique_common {
    my ($array1, $array2) = @_;

    my %freq1;
    my %freq2;
    $freq1{$_}++ for @$array1;
    $freq2{$_}++ for @$array2;

    return scalar grep {
        $freq1{$_} == 1 && exists $freq2{$_} && $freq2{$_} == 1
    } keys %freq1;
}

Raku: source code

sub count-unique-common(@array1, @array2) {
    my %freq1;
    my %freq2;

    %freq1{$_}++ for @array1;
    %freq2{$_}++ for @array2;

    return (grep {
        %freq1{$_} == 1 && (%freq2{$_} // 0) == 1
    }, keys %freq1).elems;
}

Python: source code

def count_unique_common(array1, array2):
    freq1 = {}
    freq2 = {}

    for item in array1:
        freq1[item] = freq1.get(item, 0) + 1

    for item in array2:
        freq2[item] = freq2.get(item, 0) + 1

    return sum(1 for item in freq1
               if freq1[item] == 1
               and item in freq2
               and freq2[item] == 1)

Thank you Team PWC, once again.

Happy Hacking!!

Last 5 weeks mainstream contribution stats. Thank you Team PWC for your support and encouragements.

Last 5 weeks guest contribution stats. Thank you each and every guest contributors for your time and efforts.

TOP 10 Guest Languages

Do you see your favourite language in the Top #10? If not then why not contribute regularly and make it to the top.

 1. Python     (4412)
 2. Rust       (1166)
 3. C          (1033)
 4. Haskell    (909)
 5. Ruby       (909)
 6. Lua        (894)
 7. C++        (726)
 8. Go         (686)
 9. JavaScript (639)
10. Java       (532)

Blogs with Creative Title

1. Common Beauty by Arne Sommer.

2. Common Beauty by Jorg Sommrey.

3. A Single Beauty by Matthias Muth.

4. You’ve got to get up every morning… by Packy Anderson.

5. Single and beautiful by Peter Campbell Smith.

6. Uncommon Beauty by Roger Bell_West.

7. The Common Beauty by Simon Green.

GitHub Repository Stats

1. Commits: 49,855 (+105)

2. Pull Requests: 14,182 (+34)

3. Contributors: 279

4. Fork: 352

5. Stars: 213

SPONSOR

With start of Week #355, we have a new sponsor Marc Perry until the end of year 2026. Having said we are looking for more sponsors so that we can go back to weekly winner. If anyone interested please get in touch with us at perlweeklychallenge@yahoo.com. Thanks for your support in advance. You can find more informations here.

RECAP

Quick recap of The Weekly Challenge - 375 by Mohammad Sajid Anwar.

PERL REVIEW

If you missed any past reviews then please check out the collection.

RAKU REVIEW

If you missed any past reviews then please check out the collection.

CHART

Please take a look at the charts showing interesting data.

I would like to THANK every member of the team for their valuable suggestions. Please do share your experience with us.

NEW MEMBERS

Please find out How to contribute?, if you have any doubts.

Please try the excellent tool EZPWC created by respected member Saif Ahmed of Team PWC.

GUESTS

Please check out the guest contributions for the Week #375.

Please find past solutions by respected guests. Please share your creative solutions in other languages.

Task 1: Chessboard Squares

Submitted by: Mohammad Sajid Anwar

You are given two coordinates of a square on 8x8 chessboard.

Write a script to find the given two coordinates have the same colour.

8 W B W B W B W B
7 B W B W B W B W
6 W B W B W B W B
5 B W B W B W B W
4 W B W B W B W B
3 B W B W B W B W
2 W B W B W B W B
1 B W B W B W B W
  a b c d e f g h

Example 1

Input: $c1 = "a7", $c2 = "f4"
Output: true

Example 2

Input: $c1 = "c1", $c2 = "e8"
Output: false

Example 3

Input: $c1 = "b5", $c2 = "h2"
Output: false

Example 4

Input: $c1 = "f3", $c2 = "h1"
Output: true

Example 5

Input: $c1 = "a1", $c2 = "g8"
Output: false

Task 2: Doubled Words

Submitted by: Matt Martini

You are given a string (which may contain embedded newlines) which is taken from a page on a website. The string will not contain brackets qw{ [ ] }.

Write a script that will find doubled words (such as “this this”) and highlight (wrap in brackets) each doubled word.

The script should:

- Work across lines, even finding situations where a word at the end of
  one line is repeated at the beginning of the next.

- Find doubled words despite capitalization differences, such as with
  'The the...', as well as allow differing amounts of whitespace (spaces,
  tabs, newlines, and the like) to lie between the words.

- Find doubled words even when separated by HTML tags. For example, to
  make a word bold: '...it is <B>very</B> very important...'. Only show
  lines containing doubled words.

Adapted from Mastering Regular Expressions, Third Edition by Jeffrey E. F. Friedl

Example 1

Input: $str = "you're given the job of checking the pages on a\nweb server for doubled words (such as 'this this'), a common problem\nwith documents subject to heavy editing."
Output: "web server for doubled words (such as '[this] [this]'), a common problem"

Example 2

Input: $str = "Find doubled words despite capitalization differences, such as with 'The\nthe...', as well as allow differing amounts of whitespace (spaces,\ntabs, newlines, and the like) to lie between the words."
Output: "Find doubled words despite capitalization differences, such as with '[The]\n[the]...', as well as allow differing amounts of whitespace (spaces,"

Example 3

Input: $str = "to make a word bold: '...it is <B>very</B> very important...'."
Output: "to make a word bold: '...it is <B>[very]</B> [very] important...'."

Example 4

Input: $str = "Perl officially stands for Practical Extraction and Report Language, except when it doesn't."
Output: ""

Example 5

Input: $str = "There's more than one one way to do it.\nEasy things should be easy and hard things should be possible."
Output: "There's more than [one] [one] way to do it."

By submitting a response to the challenge you agree that your name or pseudonym, any photograph you supply and any other personal information contained in your submission may be published on this website and the associated mobile app. Last date to submit the solution 23:59 (UK Time) Sunday 7th June 2026.