The Weekly Challenge: 387

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: Rearrange Binary String

10. TASK #2: Atoms Count

HEADLINES

Welcome to the Week #387 of The Weekly Challenge.

The week #386 had the least guest contributions in 2026. Even the regular contributions was not that high. I am aware some of the regular members have taken a break. I am happy that they took time to inform me about their plan. I wish them a very relax break. Hope to see you soon.

Below is my contributions to the Task #1 of Week #386.

Perl: source code

sub base_to_int ($num, $base) {
    state $chars = { map {
        substr("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/", $_, 1) => $_
        } 0 .. 63
    };

    my $val = 0;
    $val = $val * $base + $chars->{$_} for split //, $num;
    return $val;
}

Raku: source code

sub base-to-int ($num, $base) {
    state $chars = ("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/".comb Z=> 0..63).Hash;

    my $val = 0;
    $val = $val * $base + $chars{$_} for $num.comb;
    return $val;
}

Python: source code

def base_to_int(num: str, base: int) -> int:
    # Mimics Perl's state variable initialization
    if not hasattr(base_to_int, "chars"):
        charset = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/"
        base_to_int.chars = {char: i for i, char in enumerate(charset)}

    val = 0
    for char in num:
        val = val * base + base_to_int.chars[char]
    return val

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     (4560)
 2. Rust       (1211)
 3. C          (1060)
 4. Haskell    (945)
 5. Ruby       (935)
 6. Lua        (919)
 7. C++        (745)
 8. Go         (728)
 9. JavaScript (648)
10. Java       (532)

Blogs with Creative Title

1. Reverse Lanoitar by Arne Sommer.

2. All Your Base Are Belong to Rational Numbers by Bob Lied.

3. Periodic Bases by Jorg Sommrey.

4. We’re Talkin’ Algebra by Packy Anderson.

5. Hitting the bases with recurring numbers by Peter Campbell Smith.

6. A Rational Reverse by Roger Bell_West.

7. The Rational Base by Simon Green.

GitHub Repository Stats

1. Commits: 50,971 (+102)

2. Pull Requests: 14,568 (+41)

3. Contributors: 282

4. Fork: 353

5. Stars: 219

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 - 386 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 #386.

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

Task 1: Rearrange Binary String

Submitted by: Mohammad Sajid Anwar

You are given a binary string string.

Write a script to re-arrange the given binary string that all occurrences of “01” are simultaneously replaced with “10” until no occurrences of “01” exist. Finally return the total steps needed.

Example 1

Input: $str = "111000"
Output: 0

The string already has all 1s on the left and 0s on the right.
There are no occurrences of "01", so zero step needed.

Example 2

Input: $str = "00011"
Output: 4

Step 1: "00101"
Step 2: "01010"
Step 3: "10100"
Step 4: "11000"

Example 3

Input: $str = "01011"
Output: 3

Step 1: "10101"
Step 2: "11010"
Step 3: "11100"

Example 4

Input: $str = "010101"
Output: 3

Step 1: "101010"
Step 2: "110100"
Step 3: "111000"

Example 5

Input: $str = "00001"
Output: 4

Step 1: "00010"
Step 2: "00100"
Step 3: "01000"
Step 4: "10000"

Task 2: Rational Numbers

Submitted by: Mohammad Sajid Anwar

You are given a chemical formula with elements, numbers, and parentheses.

Write a script to count the total number of each type of atom by expanding all grouped multipliers. Then, format and return the final inventory as a single string sorted alphabetically by element name, including the total count only if it is greater than 1.

Example 1

Input: $formula = "((N2O)3(H2O)2)2"
Output: "H8N12O10"

Step 1: Expand the innermost parentheses
    (N2O)3 => N = 2*3 = 6, O = 1*3 = 3 => N6O3
    (H2O)2 => H = 2*2 = 4, O = 1*2 = 2 => H4O2

Step 2: Combine inside the outer parentheses
    Formula becomes: (N6O3 H4O2)2
    Sum up identical elements inside: (N6 H4 O5)2

Step 3: Apply the outer multiplier
    N = 6*2 = 12
    H = 4*2 = 8
    O = 5*2 = 10

Step 4: Sort alphabetically and format
    Alphabetical order: H, N, O
    Counts: H: 8, N: 12, O: 10

Example 2

Input: $formula = "Mg3(PO4)2"
Output: "Mg3O8P2"

Step 1: Parse ungrouped elements
    Mg3 => Mg = 3

Step 2: Expand parentheses (PO4)2
    P = 1*2 = 2
    O = 4*2 = 8

Step 3: Total up counts
    Mg = 3
    P  = 2
    O  = 8

Step 4: Sort alphabetically and format
    Alphabetical order: Mg, O, P
    Counts: Mg: 3, O: 8, P: 2

Example 3

Input: $formula = "(((H)2)3)4"
Output: "H24"

Step 1: Expand innermost level (H)2
    H = 1*2 = 2 => formula becomes ((H2)3)4

Step 2: Expand middle level (H2)3
    H = 2*3 = 6 => formula becomes (H6)4

Step 3: Expand outer level (H6)4
    H = 6*4 = 24

Step 4: Sort alphabetically and format
    Single element: H: 24

Example 4

Input: $formula = "NaCl3(O2(S10)2)2Mg"
Output: "Cl3MgNaO4S40"

Step 1: Expand innermost parentheses (S10)2
    S = 10*2 = 20 => inner formula becomes => O2S20

Step 2: Expand outer parentheses (O2S20)2
    O = 2*2  = 4
    S = 20*2 = 40

Step 3: Combine all parts
    Ungrouped start: Na (Na = 1), Cl3 (Cl = 3)
    Expanded middle: O = 4, S = 40
    Ungrouped end: Mg (Mg = 1)

Step 4: Sort alphabetically and format
    Alphabetical order: Cl (3), Mg (1), Na (1), O (4), S (40)
    Omit the number 1 for Mg and Na.

Example 5

Input: $formula = "Z2Y3(X2W)2"
Output: "W2X4Y3Z2"

Step 1: Parse ungrouped elements
    Z2 => Z = 2
    Y3 => Y = 3

Step 2: Expand parentheses (X2W)2
    X = 2*2 = 4
    W = 1*2 = 2

Step 3: Total up counts
    W = 2, X = 4, Y = 3, Z = 2

Step 4: Sort alphabetically and format
    Alphabetical order: W (2), X (4), Y (3), Z (2)

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 23rd August 2026.