The Weekly Challenge

9. TASK #1: Longest Parenthesis

HEADLINES

Welcome to the Week #346 of The Weekly Challenge.

Today is the first Monday of the month and time to declare our next Champion of the Month. With great pleasure, I announce Niels van Dijke as the next champion. He is currently ranked #29 with total score 856. He was last declared champion in Dec 2020. Congratulations Niels.

Let us welcome new guest contributor, lexi, expert hacker in Uiua. Thanks lexi for your first contributions in Uiua.

I’ve been meaning to tell the team about something for a while and I think this is the ideal moment.

The months of November through January are usually challenging for me and I’ve always had trouble with elevated anxiety and depression during these times. I’m paying attention to taking care of my health now that November has arrived. Fortunately, I benefit greatly from being a member of the PWC team because it keeps me motivated and involved. I find that keeping myself occupied and avoiding idleness is essential to keeping my equilibrium.

By the way, next month is my 50th birthday. I never celebrated my birthdays and I intend to keep that tradition going this year as well.

Seeing our team’s retired techies who enjoy coding makes me think of my own objective: to eventually be able to code just for fun after retirement. They’re really fortunate, in my opinion.

It’s time to get ready for the Advent Calendar this year, by the way. The custom of reading through blog entries and choosing one for each day is something I truly appreciate. I’m excited to carry on this year.

Please let me know if you would like to nominate any particular blog posts. I want to make sure I don’t overlook any outstanding ones!

Below is my contribution to last week’s Task #1. It doesn’t take long but gives me immense pleasure in the end and keep me motivated.

Perl

#!/usr/bin/env perl

use strict;
use warnings;
use Test::More;

my @examples = (
    { in => [1, 3, 2],             exp => "1"       },
    { in => [2, 4, 6, 5, 3],       exp => "2"       },
    { in => [1, 2, 3, 2, 4, 1],    exp => "2, 4"    },
    { in => [5, 3, 1],             exp => "0"       },
    { in => [1, 5, 1, 5, 1, 5, 1], exp => "1, 3, 5" },
);

foreach (@examples) {
    is(peak_point(@{$_->{in}}), $_->{exp});
}

done_testing;

sub peak_point {
    my @n = @_;
    return join(", ", grep {
        ($_ == 0   ? @n > 1 && $n[0]  > $n[1]  :
         $_ == $#n ? @n > 1 && $n[-1] > $n[-2] :
         $n[$_] > $n[$_-1]  && $n[$_] > $n[$_+1])
    } 0..$#n);
}

Raku

#!/usr/bin/env raku

use Test;

my @examples = (
    { in => [1, 3, 2],             exp => "1"       },
    { in => [2, 4, 6, 5, 3],       exp => "2"       },
    { in => [1, 2, 3, 2, 4, 1],    exp => "2, 4"    },
    { in => [5, 3, 1],             exp => "0"       },
    { in => [1, 5, 1, 5, 1, 5, 1], exp => "1, 3, 5" },
);

for @examples -> %example {
    is(peak-point(%example<in>), %example<exp>);
}

done-testing;

sub peak-point(@n) {
    return @n.keys.grep({
        $_ == 0             ?? @n > 1 && @n[0]   > @n[1]   !!
        $_ == @n.end        ?? @n > 1 && @n[*-1] > @n[*-2] !!
        @n[$_] > @n[$_ - 1] && @n[$_] >  @n[$_ + 1]
    }).join(", ");
}

Python

#!/usr/bin/env python3

def peak_point(nums):
    n = nums
    return ", ".join(str(i) for i in range(len(n)) if
        (i == 0 and len(n) > 1 and n[0] > n[1]) or
        (i == len(n) - 1 and len(n) > 1 and n[-1] > n[-2]) or
        (0 < i < len(n) - 1 and n[i] > n[i-1] and n[i] > n[i+1]))

def test_examples():
    examples = [
        {"in": [1, 3, 2],             "exp": "1"},
        {"in": [2, 4, 6, 5, 3],       "exp": "2"},
        {"in": [1, 2, 3, 2, 4, 1],    "exp": "2, 4"},
        {"in": [5, 3, 1],             "exp": "0"},
        {"in": [1, 5, 1, 5, 1, 5, 1], "exp": "1, 3, 5"},
    ]

    for example in examples:
        result = peak_point(example["in"])
        expected = example["exp"]
        assert result == expected, f"Failed for {example['in']}: expected '{expected}', got '{result}'"
        print(f"{example['in']} -> {result}")

if __name__ == "__main__":
    test_examples()
    print("All tests passed!")

Thank you Team PWC, once again.

Happy Hacking!!

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


`Week`	`Perl`	`Raku`	`Blog`
`341`	57	25	25
`342`	51	22	15
`343`	44	19	13
`344`	47	25	17
`345`	45	22	15

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


`Week`	`Guests`	`Contributions`	`Languages`
`341`	15	67	19
`342`	14	46	14
`343`	15	61	20
`344`	16	60	18
`345`	16	56	18

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     (3707)
 2. Rust       (1032)
 3. Ruby       (842)
 4. Haskell    (827)
 5. Lua        (785)
 6. C++        (663)
 7. C          (596)
 8. JavaScript (594)
 9. Go         (569)
10. BQN        (480)

Blogs with Creative Title

1. Last Peak by Arne Sommer.

2. I Went to the Mountains by Bob Lied.

3. The Last Peak by Jorg Sommrey.

4. Visiting the Peaks by Matthias Muth.

5. Teach Them How To Say PWC… by Packy Anderson.

6. Peak at the answers by Peter Campbell Smith.

7. Position the Visitor by Roger Bell_West.

8. Peak Visitors by Simon Green.

GitHub Repository Stats

1. Commits: 46,072 (`+113`)

2. Pull Requests: 12,921 (`+38`)

3. Contributors: 264

4. Fork: 339 (`+2`)

5. Stars: 199 (`+1`)

With start of Week #268, we have a new sponsor Lance Wicks until the end of year 2025. 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.

RECAP

Quick recap of The Weekly Challenge - 345 by Mohammad Sajid Anwar.

PERL REVIEW

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RAKU REVIEW

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CHART

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

NEW MEMBERS

lexi joined `Team PWC` as a guest contributor.

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 #345.

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

Task 1: Longest Parenthesis

Submitted by: Mohammad Sajid Anwar

You are given a string containing only ( and ).

Write a script to find the length of the longest valid parenthesis.

Example 1

Input: $str = '(()())'
Output: 6

Valid Parenthesis: '(()())'

Example 2

Input: $str = ')()())'
Output: 4

Valid Parenthesis: '()()' at positions 1-4.

Example 3

Input: $str = '((()))()(((()'
Output: 8

Valid Parenthesis: '((()))()' at positions 0-7.

Example 4

Input: $str = '))))((()('
Output: 2

Valid Parenthesis: '()' at positions 6-7.

Example 5

Input: $str = '()(()'
Output: 2

Valid Parenthesis: '()' at positions 0-1 and 3-4.

Task 2: Magic Expression

Submitted by: Mohammad Sajid Anwar

You are given a string containing only digits and a target integer.

Write a script to insert binary operators +, - and * between the digits in the given string that evaluates to target integer.

Example 1

Input: $str = "123", $target = 6
Output: ("1*2*3", "1+2+3")

Example 2

Input: $str = "105", $target = 5
Output: ("1*0+5", "10-5")

Example 3

Input: $str = "232", $target = 8
Output: ("2*3+2", "2+3*2")

Example 4

Input: $str = "1234", $target = 10
Output: ("1*2*3+4", "1+2+3+4")

Example 5

Input: $str = "1001", $target = 2
Output: ("1+0*0+1", "1+0+0+1", "1+0-0+1", "1-0*0+1", "1-0+0+1", "1-0-0+1")

Last date to submit the solution 23:59 (UK Time) Sunday 9th November 2025.