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This blog post contains the "missing comments" from my contribution to the Perl Weekly Challenge 055. If you haven't read the Task #1 Problem Description: Flip Binary you might want to do that first.

Now to document a bit more, my submission for PWC 056 Task #1.

First, please feel free to suggest a better style of exposition. At work, I usually lard my code with comments galore, but with small demonstration programs I prefer to get as much code onto one page as possible, so now I'll try to illuminate a bit more my thoughts, no promises that they will be illuminating. Of course, let me know of any outright errors you catch as well, please.

The Idea

These are some answers to the Week 87 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days (November 22, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Longest Consecutive Sequences

You are given an unsorted array of integers @N.

Write a script to find the longest consecutive sequence. Print 0 if none sequence found.

Example 1:

Input: @N = (100, 4, 50, 3, 2)
Output: (2, 3, 4)

Example 2:

Input: @N = (20, 30, 10, 40, 50)
Output: 0

Example 3:

Input: @N = (20, 19, 9, 11, 10)
Output: (9, 10, 11)

Welcome to the fifth post about the Kephra Base Object System, where I explain the need for three kinds of attributes: data, delegating and wrapping and gas a little about their properties. It is especially advised to have read the first part (scopes) and the previous part, since accessors are methods.

In case you wonder how practical this exercise is - I already implemented a slightly simpler version and currently rewrite it. It's a standalone bundle of modules with its own tests and docs named Base-Class (Kephra::Base::Class) (123kB), which depends only on the bundle Base (there are the data types) (32 kB). So once ready it could be released on CPAN without much work.

Many of you will know my good friend Peter Scott as a Perl luminary. More recently he has turned his attention and his considerable talents to focus on the future of AI, both as an unprecedented opportunity for our society...and as an unprecedented threat to our species.

A few years back, he released an excellent book on the subject, and just recently he was invited to speak on the subject at TEDx. His talk brilliantly sums up both the extraordinary possibilities and the terrible risks inherent in turning over our decision-making to systems whose capacities are increasingly growing beyond our own abilities, and perhaps soon beyond even our own understanding.

Whether our accelerating use of AI brings us utopia or extinction, the very real possibility of either outcome surely makes these twelve minutes well worth paying attention to.

On behalf of the Dancer Core Team, I’d like to announce the availability of Dancer2 0.300001. This maintenance release brings brings a revamped tutorial, fixing of a YAML-related regression, repair of an encoding bug, and a slew of documentation fixes.

The full changelog is as follows:

These are some answers to the Week 86 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a day or so (November 15, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Pair Differences

You are given an array of integers @N and an integer $A.

Write a script to find find if there exists a pair of elements in the array whose difference is $A.

Print 1 if exists otherwise 0.

Example 1:

Input: @N = (10, 8, 12, 15, 5) and $A = 7
Output: 1 as 15 - 8 = 7

Example 2:

Input: @N = (1, 5, 2, 9, 7) and $A = 6
Output: 1 as 7 - 1 = 6

Example 3:

K^th Permutation Sequence

Write a script to accept two integers n (>=1) and k (>=1). It should print the k-th permutation of n integers.

For example, n=3 and k=4, the possible permutation sequences are listed below:

123
132
213
231
312
321

The script should print the 4^th permutation sequence 231.

The straightforward way is to generate all the permutations in the correct order and then output the k^th one. To generate them, we can use recursion: To get all the permutations of n elements, start with each element and extend it with all the permutations of the remaining elements.

This is a part of Perl Weekly Challenge(PWC) #054 and the followings are related to my solution. If you want to challenge yourself on Perl, go to https://perlweeklychallenge.org, code the latest challenges, submit codes on-time (by GitHub or email) if possible, before reading my blog post.

My laptop spent about 40.5 hours for calculating the list for the extra credit in task #2. While it was calculating, I found that my code hadn't been optimized. Anyway, even if I optimized it by 50%, the wait of 20 hours could still be a record for an impatient and blunt person like me.

2nd Apr, 2020
time | number_reached
1427 1
1745 309560
1809 325441
1831 339572
1852 353486
1951 386882
2205 453250
2253 475841
2308 482951
2358 502248

3rd Apr, 2020
time | number_reached
0419 600125
1405 772771
1534 794982
1538 796651
1543 798343
1555 800112 At this point, I realized that I should do more optimization.
1558 801872
1607 803625
1630 808808
1724 822777
1730 824482
1955 859075

https://perlweeklychallenge.org/blog/weekly-challenge-054

These are some answers to the Week 85 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a day or so (November 8, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Triplet Sum

You are given an array of real numbers greater than zero.

Write a script to find if there exists a triplet (a,b,c) such that 1 < a+b+c < 2. Print 1 if you succeed otherwise 0.

Example 1:

Input: @R = (1.2, 0.4, 0.1, 2.5)
Output: 1 as 1 < 1.2 + 0.4 + 0.1 < 2

Example 2:

Input: @R = (0.2, 1.5, 0.9, 1.1)
Output: 0

Example 3:

Part 1.

On Match 20th I had keyhole surgery to repair the aortic arch.

The lining had peeled off the wall. This happens when the lining develops a tear due to (in my case) childhood and later stress. Then, blood is pumped thru the tear and thus between the lining and the wall. Where the blood ought to go is called the 'true lumen' and when it's behind the lining and thus where is should not be - which is the bad news - , is called the 'false lumen'. So it's blood pressure in the false lumen which splits the lining off the wall. I just checked that original post and now realise I did not explain that at all.

Rotate Matrix

Write a script to rotate the following matrix by given 90/180/270 degrees clockwise.

[ 1, 2, 3 ]
[ 4, 5, 6 ]
[ 7, 8, 9 ]

For example, if you rotate by 90 degrees then expected result should be like below

[ 7, 4, 1 ]
[ 8, 5, 2 ]
[ 9, 6, 3 ]

The easiest way to work with multidimensional data in Perl is PDL. Interestingly, I haven’t found a direct method to rotate a matrix in this way.

What I have found, though, was a method to transpose a matrix, which means to switch the columns and rows. The result for the sample input is

#the spiral for the simpler script
    3,  2,  1, 
    4,  X,  0, 
    5,  6,  7

These are some answers to the Week 84 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days (November 1, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Reverse Integer

You are given an integer $N.

Write a script to reverse the given integer and print the result. Print 0 if the result doesn’t fit in 32-bit signed integer.

The number 2,147,483,647 is the maximum positive value for a 32-bit signed binary integer in computing.

Example 1:

Input: 1234
Output: 4321

Example 2:

Input: -1234
Output: -4321

Example 3:

https://perlweeklychallenge.org/blog/weekly-challenge-053

It has been a little while since I played with my little PAWS and yes like many of us these days I have been just a little distracted, trip planned, trip changed, trip canceled etc etc etc.

Anyway to recap where I left off I was just getting the 'SubscribeToShard' action to work with a HTTP stream to work, after a fashion anyway. Then I got side tracked a little playing about with the problem of testing if the stream was correctly sending data down the pipe and if I was decoding it correctly.

As a byproduct of getting to the bottom of that I finally figured out what the PAWS 'Paginators' are for and I guess how to use them.

I noticed the odd "NextToken" tag in some of the Boto Json files as well most of the services have a ''paginators-1.json' definition file as well and looking at the Kinesis pod I see that there paginators listed.

PAGINATORS
Paginator methods are helpers that repetitively call methods that return partial results

…

Continuing from extraction of coronavirus spike protein sequences I decided to compare them and see if any mutations could be found. To do this I needed to align sequences to each other and get multiple sequence alignment. There are many tools that might be used and I have chosen MUSCLE as it is fast, easy to use and accurate enough. However, other tools such as MAFFT or T-Coffee should also work well and could give more accurate alignments in more complicated cases than the one I was dealing with.

Let’s gain some MUSCLE

For analysis of multiple sequence alignment (MSA) I chose BioPerl module Bio::Tools::Run::Alignment::Muscle. I found out that in order to install this module I need some dependencies. This worked for me with Perl v5.30 PDL edition on Windows:

cpanm -n XML::DOM::XPath cpanm Bio::DB::EUtilities Bio::Tools::Run::Alignment::Muscle

Next I installed MUSCLE

These are some answers to the Week 83 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a couple of days (October 25, 2020). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Words Length

You are given a string $S with 3 or more words.

Write a script to find the length of the string except the first and last words ignoring whitespace.

Example 1:

Input: $S = "The Weekly Challenge"

Output: 6

Example 2:

Input: $S = "The purpose of our lives is to be happy"

Output: 23

Words Length in Raku

I lost a friend of mine, Jeff Goff (aka DrForr), who passed away on 13th March, 2020, while snorkeling with a group in the Bahamas. He will be missed by many of his friends. May his soul rest in peace.

Most of the time last month was occupied by COVID-19. Being a type-2 diabetic didn't help the cause either. I have suffered with consistent cough all my life. It is really scary when think from COVID-19 point of view. I have survived so far by the grace of ALLAH s.w.t.

I have been working from home since the first week of March. I have been kind of self quarantined. Kids, specially the twins (3 years old) not allowed to play with me. It is really hard to focus on work but somehow I have managed so far. I am getting used to it now.

This is a part of Perl Weekly Challenge(PWC) #053 and the followings are related to my solution. If you want to challenge yourself on Perl, go to https://perlweeklychallenge.org, code the latest challenges, submit codes on-time (by GitHub or email) if possible, before reading my blog post.

Do tell me if I am wrong or you strongly oppose my statements!

( The first task is simple.
Not much to say about this task.
4-3 = 1; 4-2 =2; 4-1 = 3.
(Honestly I haven't coded on it. :P) )

Here for the second task.

Somehow, it looks like those base-10 special property tasks, e.g. multiples consisting of 1's and 0's(#49), stepping numbers(#052), gapful number(#047) or colourful numbers(#051). Like those base-10 tasks, the possible brute-force way is: list out all possible combinations or permutations, and then exclude unfit candidates (equivalently, only print suitable candidates).