The Weekly Challenge: 398

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: Divisible Average

10. TASK #2: String Difference

HEADLINES

Welcome to the Week #398 of The Weekly Challenge.

Today’s the first Monday of the month and time to declare the Champion of the Month. With great pleasure, I announce E. Choroba the next champion. He is currently ranked #12 with total scores 1684. As of today he has contributed 783 solutions in Perl and 59 blog posts.

Below is my contributions to the Week #397.

[Task #1 - Perl]: source code

sub smallest_greater_absent(@arr) {
    my %seen = map { $_ => 1 } @arr;
    my $avg  = sum(@arr) / @arr;
    my $n    = int($avg) + 1;
    $n = 1 if $n < 1;
    $n++ while $seen{$n};
    return $n;
}

[Task #2 - Perl]: source code

sub sort_binary_reflection {
    my $ref = sub { oct("0b" . reverse sprintf("%b", shift)) };
    return [ sort { $ref->($a) <=> $ref->($b) || $a <=> $b } @_ ];
}

[Task #1 - Raku]: source code

sub smallest-greater-absent(*@arr) {
    my %seen = @arr.map({ $_ => True });
    my $avg  = @arr.sum / @arr.elems;
    my $n    = $avg.Int + 1;
    $n = 1 if $n < 1;
    $n++ while %seen{$n};
    return $n;
}

[Task #2 - Raku]: source code

sub sort-binary-reflection(*@arr) {
    my $ref = sub ($x) { :2($x.base(2).flip) };
    return [ @arr.sort({ $ref($^a) <=> $ref($^b) || $^a <=> $^b }) ];
}

[Task #1 - Python]: source code

def smallest_greater_absent(arr):
    seen = {x: True for x in arr}
    avg  = sum(arr) / len(arr)
    n    = int(avg) + 1
    if n < 1:
        n = 1
    while n in seen:
        n += 1
    return n

[Task #2 - Python]: source code

def sort_binary_reflection(arr):
    def ref(x):
        return int(bin(x)[2:][::-1], 2)

    return sorted(arr, key=lambda x: (ref(x), x))

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     (4704)
 2. Rust       (1255)
 3. C          (1082)
 4. Haskell    (973)
 5. Ruby       (959)
 6. Lua        (943)
 7. C++        (764)
 8. Go         (736)
 9. JavaScript (664)
10. Java       (534)

Blogs with Creative Title

1. Absent Reflection by Arne Sommer.

2. Reflection by Bob Lied.

3. Absent Reflections by Jorg Sommrey.

4. Reflections on Missing Numbers by Matthias Muth.

5. Latch on to the affirmative by Packy Anderson.

6. Positive reflection by Peter Campbell Smith.

7. Absent Reflection by Roger Bell_West.

8. An average reflection by Simon Green.

GitHub Repository Stats

1. Commits: 51,926 (+116)

2. Pull Requests: 14,903 (+38)

3. Contributors: 281

4. Fork: 352

5. Stars: 221

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 - 397 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 #397.

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

Task 1: Divisible Average

Submitted by: Mohammad Sajid Anwar

You are given an array of positive integers.

Write a script to return the closest integer to the mean value of all even integers that are divisible by 3. If none is divisible, return 0.

Example 1

Input: @arr = (18, 5, 7, 11)
Output: 18

18 is the only even number and divisible by 3.
Average: 18 / 1 = 18.

Example 2

Input: @arr = (6, 12, 18, 24, 30, 40)
Output: 18

The qualifying numbers are 6, 12, 18, 24, and 30.
Average: (6 + 12 + 18 + 24 + 30) / 5 = 90 / 5 = 18

Example 3

Input: @arr = (3, 9, 15, 21, 27)
Output: 0

None of the elements are even.
Since no elements qualify, return 0.

Example 4

Input: @arr = (6, 12, 14, 20)
Output: 9

The qualifying numbers are 6 and 12.
Average: (6 + 12) / 2 = 9.

Example 5

Input: @arr = (6, 6, 6, 12, 12)
Output: 8

All five numbers are even and divisible by 3.
Average: (6 + 6 + 6 + 12 + 12) / 5 = 8.4 => 8

Task 2: String Difference

Submitted by: Mohammad Sajid Anwar

You are given an array of equal length strings.

Write a script to find the difference integer array of each word in the given array. There will be one word with a different array; return that word.

Each words[i] can be converted into a difference integer array difference[i] of length n - 1 where difference[i][j] = words[i][j+1] - words[i][j]

Example 1

Input: @words = ("ab", "bc", "cd", "zy")
Output: "zy"

"ab" => [1 - 0] = [1]
"bc" => [2 - 1] = [1]
"cd" => [3 - 2] = [1]
"zy" => [24 - 25] = [-1]

Example 2

Input: @words = ("cba", "fed", "azy")
Output: "azy"

"cba" => [1 - 2, 0 - 1] = [-1, -1]
"fed" => [4 - 5, 3 - 4] = [-1, -1]
"azy" => [25 - 0, 24 - 25] = [25, -1]

Example 3

Input: @words = ("pop", "ada", "beb", "cfc")
Output: "pop"

"pop" => [14 - 15, 15 - 14] = [-1, 1]
"ada" => [3 - 0, 0 - 3] = [3, -3]
"beb" => [4 - 1, 1 - 4] = [3, -3]
"cfc" => [5 - 2, 2 - 5] = [3, -3]

Example 4

Input: @words = ("aaaa", "zzzz", "mmmm", "aaba")
Output: "aaba"

"aaaa" => [0 - 0, 0 - 0, 0 - 0] = [0, 0, 0]
"zzzz" => [25 - 25, 25 - 25, 25 - 25] = [0, 0, 0]
"mmmm" => [12 - 12, 12 - 12, 12 - 12] = [0, 0, 0]
"aaba" => [0 - 0, 1 - 0, 0 - 1] = [0, 1, -1]

Example 5

Input: @words = ("aceg", "bdfh", "cegi", "azbz")
Output: "azbz"

"aceg" => [2 - 0, 4 - 2, 6 - 4] = [2, 2, 2]
"bdfh" => [3 - 1, 5 - 3, 7 - 5] = [2, 2, 2]
"cegi" => [4 - 2, 6 - 4, 8 - 6] = [2, 2, 2]
"azbz" => [25 - 0, 1 - 25, 25 - 1] = [25, -24, 24]

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 8th November 2026.