Perl Weekly Challenge

HEADLINES

Last Friday was the first day of Ramadan in the United Kingdom. Because of the fasting during the day, I try to preserve my energy and use it when necessary. You will probably notice delay in acceptance of your contributions during this month. I may not be able to respond to your email as promptly as before. Please bear with me in this holy month.

I would like to take this opportunity to thank all the regulars who have been blogging about their solutions and all those new members who are actively blogging straight away. You are the star contributors. I would urge all members to read the blog by fellow members. It is always complete package. Please follow the RECAPS if you are not sure where to look for blogs.

For the last two weeks, you have been dealing with Binary Tree related tasks. During this period, I was looking for a decent way to print Binary Tree. Many Team PWC members tried it and came up with unique way to print binary tree. Of all, I liked the one proposed by Scimon Proctor as solution to the task Path Sum. There is another interpretation by Colin Crain as solution to the task Invert Tree. Please do check them out and let us know what you think.

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

RECAP

Quick recap of the “Perl Weekly Challenge - 057” by Mohammad S Anwar.

PERL REVIEW

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

RAKU REVIEW

Please checkout Raku solutions review of the “Perl Weekly Challenge - 054” by Laurent Rosenfeld.

If you missed any past reviews then please checkout 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 give it a try to an excellent tool EZPWC created by respected member Saif Ahmed of Team PWC.

GUESTS

Ben Davies shared solutions to Task #1 and Task #2 in Idris.

Leo Manfredi shared solution to Task #2 in Python.

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

User Person shared solution to Task #2 in Python.

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

TASK #1 › Compare Version

Reviewed by Ryan Thompson

Compare two given version number strings v1 and v2 such that:

If v1 > v2 return 1
If v1 < v2 return -1
Otherwise, return 0

The version numbers are non-empty strings containing only digits, and the dot (“.”) and underscore (“_”) characters. (“_” denotes an alpha/development version, and has a lower precedence than a dot, “.”). Here are some examples:

   v1   v2    Result
------ ------ ------
  0.1 < 1.1     -1
  2.0 > 1.2      1
  1.2 < 1.2_5   -1
1.2.1 > 1.2_1    1
1.2.1 = 1.2.1    0

Version numbers may also contain leading zeros. You may handle these how you wish, as long as it’s consistent.

TASK #2 › Ordered Lineup

Reviewed by Ryan Thompson

Write a script to arrange people in a lineup according to how many taller people are in front of each person in line. You are given two arrays. @H is a list of unique heights, in any order. @T is a list of how many taller people are to be put in front of the corresponding person in @H. The output is the final ordering of people’s heights, or an error if there is no solution.

Here is a small example:

@H = (2, 6, 4, 5, 1, 3) # Heights
@T = (1, 0, 2, 0, 1, 2) # Number of taller people in front

The ordering of both arrays lines up, so H[i] and T[i] refer to the same person. For example, there are 2 taller people in front of the person with height 4, and there is 1 person in front of the person with height 1.

Here is a diagram of the input arrays @H and @T:

Finally, here is one possible solution that satisfies @H and @T:

As per the last diagram, your script would then output the ordering (5, 1, 2, 6, 3, 4) in this case. (The leftmost element is the “front” of the array.)

Here’s a 64-person example, with answer provided:

# Heights
@H = (27, 21, 37,  4, 19, 52, 23, 64,  1,  7, 51, 17, 24, 50,  3,  2,
      34, 40, 47, 20,  8, 56, 14, 16, 42, 38, 62, 53, 31, 41, 55, 59,
      48, 12, 32, 61,  9, 60, 46, 26, 58, 25, 15, 36, 11, 44, 63, 28,
       5, 54, 10, 49, 57, 30, 29, 22, 35, 39, 45, 43, 18,  6, 13, 33);

# Number taller people in front
@T = ( 6, 41,  1, 49, 38, 12,  1,  0, 58, 47,  4, 17, 26,  1, 61, 12,
      29,  3,  4, 11, 45,  1, 32,  5,  9, 19,  1,  4, 28, 12,  2,  2,
      13, 18, 19,  3,  4,  1, 10, 16,  4,  3, 29,  5, 49,  1,  1, 24,
       2,  1, 38,  7,  7, 14, 35, 25,  0,  5,  4, 19, 10, 13,  4, 12);

# Expected answer
@A = (35, 23,  5, 64, 37,  9, 13, 25, 16, 44, 50, 40,  2, 27, 36,  6,
      18, 54, 20, 39, 56, 45, 12, 47, 17, 33, 55, 30, 26, 51, 42, 53,
      49, 41, 32, 15, 22, 60, 14, 46, 24, 59, 10, 28, 62, 38, 58, 63,
       8, 48,  4,  7, 31, 19, 61, 43, 57, 11,  1, 34, 21, 52, 29,  3);

You’re free to come up with your own inputs. Here is a 1000-person list, if you like!

On a serious note, during this pandemic, please be kind to your local grocery store employees. They don’t get paid enough for this!

Last date to submit the solution 23:59 (UK Time) Sunday 3rd May 2020.