The Weekly Challenge: 366

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: Count Prefixes

10. TASK #2: Valid Valid Times

HEADLINES

Welcome to the Week #366 of The Weekly Challenge.

We reached the target last week - well done Team PWC. This is the sixth time out of eleven weeks this year. Even the guest contribution matched the best week of the year.

Back to back contributions from Abigail, Awk, Bash, C, Go, Perl, Python, Ruby, and Tcl, thank you.

Special mention to Paulo Custodio and Lubos Kolouch for keeping the spirit high. Thanks to Paulo Custodio's recent push, C has moved up from #5 to #3. Ruby currently sits at #4, but it’s not anywhere close to C.

Android App Update:

A big shout-out to Packy Anderson, Peter Campbell Smith, Paulo Custodio, and Reinier Maliepaard for the constructive suggestions. Luckily, I managed to implement all the requested changes. If any of you have joined The Weekly Challenge Testers group then please make sure you’ve installed the app and keep it on for a minimum of 14 days as required by Google. For those who did install the app, please make sure you get the regular updates so you actually see the latest changes. The last updated version was v1.0.7, just for the record. The next build version 1.0.8 is on the way as we speak. If anyone wants to help me test my first mobile app, please send me your email address linked to your Google Play Store account, and I will send you the invite. You don’t need to use the app every hour - just opening it occasionally to browse recent challenges or recaps will help show Google that the app has active engagement.

Community Shout-out

I continue to receive nice reviews of the new-look website. Honestly it makes me very happy. Now that we have a mobile app in the making, I see real progress. One thing, I miss in the new design, the members’ cute profile photos. We do have some, which look nice on the website and app, but we want more. So if you’ve used a profile photo on the internet, please share it with us too. The profile photo requirement is 130x130 pixels and JPG format. I assume, you’re ok with me using the profile photo on the website and mobile app.

One more thing: while working on the Champions screen for the mobile app, I noticed we stopped the tradition of interviewing champions. I want to start that again by reaching out to all past champions. It’s always encouraging to hear the personal side as well. I will prepare the interview format and share it with you. If you do recieve the invite, please take the time to respond.

Normally, Mark Anderson or Eric Cheung is the first to submit the solutions to the weekly challenge. I’m not sure, if the challenge release time works in their favour, but last week Neils van Dijke beat them both and became the first contributor. I am not suggesting, there’s a race to be the first contributor - I’m just pointing out a change in pattern, nothing else.

Below is my contributions to the Task #1 of Week #364.

Perl: source code

sub alphabet_index_digit_sum {
    my ($s, $k) = @_;

    my $n = join "", map{ ord($_) - 96 } split "", $s;
    $n = eval join "+", split "", $n for 1..$k;
    return $n;
}

Raku: source code

sub alphabet-index-digit-sum (@args) {
    my ($s, $k) = @args;

    my $n = join "", map { $_.ord - 96 }, $s.comb;
    $n = [+] $n.comb for 1..$k;
    return $n;
}

Python: source code

def alphabet_index_digit_sum(s, k):
    n = ''.join(str(ord(c) - 96) for c in s)
    for _ in range(k):
        n = str(sum(int(d) for d in n))
    return int(n)

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     (4255)
 2. Rust       (1123)
 3. C          (921)
 3. Ruby       (880)
 5. Haskell    (875)
 6. Lua        (859)
 7. C++        (702)
 8. Go         (662)
 9. JavaScript (627)
10. Java       (530)

Blogs with Creative Title

1. A Token Alphabet by Arne Sommer.

2. Sum Tokens and Count Digits by Jorg Sommrey.

3. regexps to rule them all! by Luca Ferrari.

4. Are Post Alphabits a Token Breakfast Cereal? by Marc Perry.

5. Splitting and Summing and Checking and Counting by Matthias Muth.

6. I’ll be the smartest bird the world has ever seen! by Packy Anderson.

7. Lots of counting by Peter Campbell Smith.

8. Alphabet Digit Counter Token by Roger Bell_West.

9. Counting the index by Simon Green.

GitHub Repository Stats

1. Commits: 48,562 (+195)

2. Pull Requests: 13,791 (+50)

3. Contributors: 275

4. Fork: 349

5. Stars: 212 (+1)

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 - 365 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 #365.

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

Task 1: Count Prefixes

Submitted by: Mohammad Sajid Anwar

You are given an array of words and a string (contains only lowercase English letters).

Write a script to return the number of words in the given array that are a prefix of the given string.

Example 1

Input: @array = ("a", "ap", "app", "apple", "banana"), $str = "apple"
Output: 4

Example 2

Input: @array = ("cat", "dog", "fish"), $str = "bird"
Output: 0

Example 3

Input: @array = ("hello", "he", "hell", "heaven", "he"), $str = "hello"
Output: 4

Example 4

Input: @array = ("", "code", "coding", "cod"), $str = "coding"
Output: 3

Example 5

Input: @array = ("p", "pr", "pro", "prog", "progr", "progra", "program"), $str = "program"
Output: 7

Task 2: Valid Times

Submitted by: Mohammad Sajid Anwar

You are given a time in the form ‘HH:MM’. The earliest possible time is ‘00:00’ and the latest possible time is ‘23:59’. In the string time, the digits represented by the ‘?’ symbol are unknown, and must be replaced with a digit from 0 to 9.

Write a script to return the count different ways we can make it a valid time.

Example 1

Input: $time = "?2:34"
Output: 3

0 -> "02:34" valid
1 -> "12:34" valid
2 -> "22:34" valid

Example 2

Input: $time = "?4:?0"
Output: 12

Hours: tens digit ?, ones digit 4 -> can be 04, and 14 (2 possibilities)
Minutes: tens digit ?, ones digit 0 -> tens can be 0-5 (6 possibilities)

Total: 2 × 6 = 12

Example 3

Input: $time = "??:??"
Output: 1440

Hours: from 00 to 23 -> 24 possibilities
Minutes: from 00 to 59 -> 60 possibilities

Total: 24 × 60 = 1440

Example 4

Input: $time = "?3:45"
Output: 3

If tens digit is 0 or 1 -> any ones digit works, so 03 and 13 are valid
If tens digit is 2 -> ones digit must be 0-3, but here ones digit is 3, so 23 is valid

Therefore: 0,1,2 are all valid -> 3 possibilities

Example 5

Input: $time = "2?:15"
Output: 4

Tens digit is 2, so hours can be 20-23
Ones digit can be 0,1,2,3 (4 possibilities)

Therefore: 4 valid times

Last date to submit the solution 23:59 (UK Time) Sunday 29th March 2026.