Add pdl solution to challenge 88

3 files changed, 45 insertions, 0 deletions

diff --git a/challenge-088/wlmb/README b/challenge-088/wlmb/README
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+Solution by Luis Mochan wlmb
diff --git a/challenge-088/wlmb/perl/ch-1.pl b/challenge-088/wlmb/perl/ch-1.pl
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+#!/usr/bin/env perl
+# Perl Weekly Challenge 88 task 1 array of product
+# Given a matrix $N[i] produce a matrix $M[i]= of products of $N[j] excluding $N[i]
+use warnings;
+use strict;
+use feature qw(say);
+
+say join " ", "Example 1:", array_of_products(5,2,1,4,3);
+say join " ", "Example 2:", array_of_products(2,1,4,3);
+
+sub array_of_products {
+    use PDL; #use the perl data language
+    use PDL::NiceSlice;
+    my $input =pdl(@_); #input piddle (PDL array)
+    my $matrix=$input(:,*$input->dim(0))->copy; #replicate row to produce a matrix
+    $matrix->diagonal(0,1).=1; #replace diagonal by 1's
+    my $output=$matrix->prodover; #multiply elements row-wise
+    return $output->list; #convert to perl list
+}
diff --git a/challenge-088/wlmb/perl/ch-2.pl b/challenge-088/wlmb/perl/ch-2.pl
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+#!/usr/bin/env perl
+# Perl Weekly Challenge 88 task 2 Spiral Matrix
+# Print elements of matrix along spiral
+use warnings;
+use strict;
+use feature qw(say);
+
+say join " ", "Example 1:", spiral_matrix([1,2,3],[4,5,6],[7,8,9]);
+say join " ", "Example 2:", spiral_matrix([1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]);
+
+sub spiral_matrix {
+    use PDL; #use the perl data language
+    use PDL::NiceSlice;
+    my $input =pdl(@_); #input piddle (PDL 2D array)
+    say $input;
+    my @output;
+    return if $input->dim(1)==0; # 0 rows no elements
+    while($input->dim(0) > 0){ #until no more columns
+	push @output, $input->(:,(0))->list; # walk through row
+	last if $input->dim(1)==1; # no more rows
+	$input=$input->(-1:0,1:-1) #reflect rows, remove one row
+	    ->transpose; # rotate
+    }
+    return @output
+}