Perl Weekly Challenge 324.
My solutions (task 1 and task 2 ) to the The Weekly Challenge - 324.
Task 1: 2D Array
Submitted by: Mohammad Sajid Anwar
You are given an array of integers and two integers $r amd $c.
Write a script to create two dimension array having $r rows and $c columns using the given array.
Example 1
Input: @ints = (1, 2, 3, 4), $r = 2, $c = 2
Output: ([1, 2], [3, 4])
Example 2
Input: @ints = (1, 2, 3), $r = 1, $c = 3
Output: ([1, 2, 3])
Example 3
Input: @ints = (1, 2, 3, 4), $r = 4, $c = 1
Output: ([1], [2], [3], [4])
The Perl Data Language PDL has operators to reshape arrays, making this
problem quite trivial.
Example 1:
perl -MPDL -E '
($r, $c, @i)=@ARGV; say "r=$r, c=$c, array=", pdl(@i), "->", pdl(@i)->reshape($c,$r)
' 2 2 1 2 3 4
Results:
r=2, c=2, array=[1 2 3 4]->
[
[1 2]
[3 4]
]
Example 2:
perl -MPDL -E '
($r, $c, @i)=@ARGV; say "r=$r, c=$c, array=", pdl(@i), "->", pdl(@i)->reshape($c,$r)
' 1 3 1 2 3
Results:
r=1, c=3, array=[1 2 3]->
[
[1 2 3]
]
Example 3:
perl -MPDL -E '
($r, $c, @i)=@ARGV; say "r=$r, c=$c, array=", pdl(@i), "->", pdl(@i)->reshape($c,$r)
' 4 1 1 2 3 4
Results:
r=4, c=1, array=[1 2 3 4]->
[
[1]
[2]
[3]
[4]
]
The full code is similar:
1 # Perl weekly challenge 324
2 # Task 1: 2D Array
3 #
4 # See https://wlmb.github.io/2025/06/02/PWC324/#task-1-2d-array
5 use v5.36;
6 use PDL;
7 die <<~"FIN" unless @ARGV >= 3;
8 Usage: $0 R C D1 D2...
9 to reshape the array (D1 D2...) into a matrix with
10 R rows and C columns
11 FIN
12 my ($rows, $cols, @array)=@ARGV;
13 die "Number of elements should equal RxC" unless $rows*$cols==@array;
14 my $array=pdl(@array);
15 my $reshaped=$array->copy->reshape($cols, $rows);
16 say "rows=$rows, cols=$cols, array= $array -> $reshaped";
Example:
./ch-1.pl 2 2 1 2 3 4
./ch-1.pl 1 3 1 2 3
./ch-1.pl 4 1 1 2 3 4
Results:
rows=2, cols=2, array= [1 2 3 4] ->
[
[1 2]
[3 4]
]
rows=1, cols=3, array= [1 2 3] ->
[
[1 2 3]
]
rows=4, cols=1, array= [1 2 3 4] ->
[
[1]
[2]
[3]
[4]
]
Task 2: Total XOR
Submitted by: Mohammad Sajid Anwar
You are given an array of integers.
Write a script to return the sum of total XOR for every subset of given array.
Example 1
Input: @ints = (1, 3)
Output: 6
Subset [1], total XOR = 1
Subset [3], total XOR = 3
Subset [1, 3], total XOR => 1 XOR 3 => 2
Sum of total XOR => 1 + 3 + 2 => 6
Example 2
Input: @ints = (5, 1, 6)
Output: 28
Subset [5], total XOR = 5
Subset [1], total XOR = 1
Subset [6], total XOR = 6
Subset [5, 1], total XOR => 5 XOR 1 => 4
Subset [5, 6], total XOR => 5 XOR 6 => 3
Subset [1, 6], total XOR => 1 XOR 6 => 7
Subset [5, 1, 6], total XOR => 5 XOR 1 XOR 6 => 2
Sum of total XOR => 5 + 1 + 6 + 4 + 3 + 7 + 2 => 28
Example 3
Input: @ints = (3, 4, 5, 6, 7, 8)
Output: 480
I’ll assume all integers are different, or that subset actually
means sublist, so I don’t have to check for repetitions. I build a
recursive routine that takes a list and returns the xor’s of all
its sublists. If the array is empty, it returns 0. If not, it
separates the first element, recurses over the remaining elements and
returns a list with and without~xor~-ing the first element with the
resulting list. Finally, I sum all the elements of the list. I use
reduce and sum from List::Util. The results takes a one-liner.
Example 1:
perl -MList::Util=reduce,sum -E '
sub f(@x){@x?(f(@x[1..@x-1]), map {$x[0]^$_}f(@x[1..@x-1])):(0)}say "@ARGV -> ",sum f(@ARGV)
' 1 3
Results:
1 3 -> 6
Example 2:
perl -MList::Util=reduce,sum -E '
sub f(@x){@x?(f(@x[1..@x-1]), map {$x[0]^$_}f(@x[1..@x-1])):(0)}say "@ARGV -> ",sum f(@ARGV)
' 5 1 6
Results:
5 1 6 -> 28
Example 3:
perl -MList::Util=reduce,sum -E '
sub f(@x){@x?(f(@x[1..@x-1]), map {$x[0]^$_}f(@x[1..@x-1])):(0)}say "@ARGV -> ",sum f(@ARGV)
' 3 4 5 6 7 8
Results:
3 4 5 6 7 8 -> 480
The full code is similar:
1 # Perl weekly challenge 324
2 # Task 2: Total XOR
3 #
4 # See https://wlmb.github.io/2025/06/02/PWC324/#task-2-total-xor
5 use v5.36;
6 use List::Util qw(reduce sum);
7 sub f(@x){
8 if(@x){
9 my ($first, @rest)=@x;
10 my @reduced=f(@rest);
11 return @reduced, map{$first^$_}@reduced;
12 }
13 return (0);
14 }
15 say "@ARGV -> ", sum f(@ARGV);
Example:
./ch-2.pl 1 3
./ch-2.pl 5 1 6
./ch-2.pl 3 4 5 6 7 8
Results:
1 3 -> 6
5 1 6 -> 28
3 4 5 6 7 8 -> 480
/;