Perl Weekly Challenge - 069

Monday, Jul 13, 2020| Tags: Perl, Raku


With three members joining Team PWC, we now have 173 members. I welcome all of them with open arms. I would like to mention one member explicitly Myoungjin Jeon, why? He is someone who did Perl long time ago and currently a Chef by profession. What impressed me the most about him is that he never let his love for Perl die. I hope he finds the weekly challenge interesting to keep him going.

Apology for not doing Live Coding video for “Perl Weekly Challenge - 068”. I promise to do it together with next week challenge. In the meantime, if you want to watch past videos then please check out my YouTube Channel. If you like the videos then don’t forget to subscribe the channel.

Last but not the least, I would like to thank each and every member for their support and encouragement.


Quick recap of the “Perl Weekly Challenge - 068” by Mohammad S Anwar.


Please checkout Perl solutions review of the “Perl Weekly Challenge - 067” by Colin Crain.

If you missed any past reviews then please checkout the collection.


If you missed any past reviews then please checkout the collection.


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.


We have a private Early Bird Club, whose members have the privilege to check out the weekly challenge before Monday, the launch day. Not only that they get more time to work on the tasks. Joining is very easy, just drop me a line at and you are good to go.

1. Vinod Kumar Pal joined the team to learn Perl.

2. Myoungjin Jeon, Perl enthusiast joined the team from Sydney, Australia.

I’m a Japanese chef. I used to write some tiny codes in Perl from 2002 to 201. They are only for personal study and curiosity. There are not so much about talking my background but I love free software and GNU/Linux and use them everyday.

3. Simon Green, Perl enthusiast joined the team from Sydney, Australia.

I first used Perl in 1995 at an ISP when you still had to explain to your parents what the Internet was. Since then I’ve used Perl as my main language at most jobs, although am using Python more recently.

Please find out How to contribute?, if you have any doubts.

Please give it a try to an excellent tool EZPWC created by respected member Saif Ahmed of Team PWC.


Richard Park shared solutions to Task #1 and Task #2 in APL.

Ulrich Rieke shared solution to Task #2 in C++.

Ulrich Rieke shared solution to Task #2 in Haskell.

Walt Mankowski shared solutions to Task #1 and Task #2 in Python.

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

TASK #1 › Strobogrammatic Number

Submitted by: Mohammad S Anwar

A strobogrammatic number is a number that looks the same when looked at upside down.

You are given two positive numbers $A and $B such that 1 <= $A <= $B <= 10^15.

Write a script to print all strobogrammatic numbers between the given two numbers.


Input: $A = 50, $B = 100
    Output: 69, 88, 96

TASK #2 › 0/1 String

Submitted by: Mohammad S Anwar

A 0/1 string is a string in which every character is either 0 or 1.

Write a script to perform switch and reverse to generate S30 as described below:


Every 0 becomes 1 and every 1 becomes 0. For example, “101” becomes “010”.


The string is reversed. For example, "001” becomes “100”.

UPDATE (2020-07-13 17:00:00):

It was brought to my notice that generating S1000 string would be nearly impossible. So I have decided to lower it down to S30. Please follow the rule as below:

S0 = “”
S1 = “0”
S2 = “001”
S3 = “0010011”
SN = SN-1 + “0” + switch(reverse(SN-1))

Last date to submit the solution 23:59 (UK Time) Sunday 19th July 2020.


If you have any suggestions or ideas then please do share with us.

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