Perl & Raku solutions to Tasks 1 & 2 of the Perl Weekly Challenge #073

On branch branch-for-challenge-073
Changes to be committed:
	new file:   challenge-073/athanasius/perl/ch-1.pl
	new file:   challenge-073/athanasius/perl/ch-2.pl
	new file:   challenge-073/athanasius/raku/ch-1.raku
	new file:   challenge-073/athanasius/raku/ch-2.raku

4 files changed, 460 insertions, 0 deletions

diff --git a/challenge-073/athanasius/perl/ch-1.pl b/challenge-073/athanasius/perl/ch-1.pl
new file mode 100644
index 0000000000..0fb9a24dcf
--- /dev/null
+++ b/challenge-073/athanasius/perl/ch-1.pl
@@ -0,0 +1,106 @@
+#!perl
+
+################################################################################
+=comment
+
+Perl Weekly Challenge 073
+=========================
+
+Task #1
+-------
+*Min Sliding Window*
+
+Submitted by: Mohammad S Anwar
+
+You are given an array of integers @A and sliding window size $S.
+
+Write a script to create an array of min from each sliding window.
+
+Example
+
+Input: @A = (1, 5, 0, 2, 9, 3, 7, 6, 4, 8) and $S = 3
+Output: (0, 0, 0, 2, 3, 3, 4, 4)
+
+[(1 5 0) 2 9 3 7 6 4 8] = Min (0)
+[1 (5 0 2) 9 3 7 6 4 8] = Min (0)
+[1 5 (0 2 9) 3 7 6 4 8] = Min (0)
+[1 5 0 (2 9 3) 7 6 4 8] = Min (2)
+[1 5 0 2 (9 3 7) 6 4 8] = Min (3)
+[1 5 0 2 9 (3 7 6) 4 8] = Min (3)
+[1 5 0 2 9 3 (7 6 4) 8] = Min (4)
+[1 5 0 2 9 3 7 (6 4 8)] = Min (4)
+
+=cut
+################################################################################
+
+#--------------------------------------#
+# Copyright © 2020 PerlMonk Athanasius #
+#--------------------------------------#
+
+use strict;
+use warnings;
+use Const::Fast;                    # Exports const()
+use Getopt::Long;                   # Exports GetOptions()
+use List::Util     qw( min );
+use PerlX::Window;                  # Exports window() and @window
+use Regexp::Common qw( number );    # Exports %RE{num}
+
+const my $USAGE =>
+"Usage:
+  perl $0 [-S <Natural>] [-A <Int> +]
+
+    -S <Natural>    Sliding window size: 0 < S <= integers in A
+    -A <Int> +      Sequence of one or more integers\n";
+
+#-------------------------------------------------------------------------------
+BEGIN
+#-------------------------------------------------------------------------------
+{
+    $| = 1;
+    print "\nChallenge 073, Task #1: Min Sliding Window (Perl)\n\n";
+}
+
+#===============================================================================
+MAIN:
+#===============================================================================
+{
+    my ($S, @A) = parse_command_line();
+
+    printf "Input: \@A = (%s) and \$S = %d\n", join(', ', @A), $S;
+
+    my   @minima;
+    push @minima, min(@window) while window(@A, $S);
+
+    printf "Output: (%s)\n", join(', ', @minima);
+}
+
+#-------------------------------------------------------------------------------
+sub parse_command_line
+#-------------------------------------------------------------------------------
+{
+    my ($S, @A);
+
+    GetOptions
+    (
+        'S=i'     => \$S,
+        'A=i{1,}' => \@A,
+    )                       or die $USAGE;
+
+    scalar @ARGV == 0       or die $USAGE;
+    is_int($S) && $S > 0    or die $USAGE;
+    is_int($_)              or die $USAGE for @A;
+    $S <= scalar @A         or die $USAGE;
+
+    return ($S, @A);
+}
+
+#-------------------------------------------------------------------------------
+sub is_int
+#-------------------------------------------------------------------------------
+{
+    my ($n) = @_;
+
+    return defined($n) && $n =~ / \A $RE{num}{int} \z /x;
+}
+
+################################################################################
diff --git a/challenge-073/athanasius/perl/ch-2.pl b/challenge-073/athanasius/perl/ch-2.pl
new file mode 100644
index 0000000000..a62a6dec8e
--- /dev/null
+++ b/challenge-073/athanasius/perl/ch-2.pl
@@ -0,0 +1,145 @@
+#!perl
+
+################################################################################
+=comment
+
+Perl Weekly Challenge 073
+=========================
+
+Task #2
+-------
+*Smallest Neighbour*
+
+Submitted by: Mohammad S Anwar
+
+You are given an array of integers @A.
+
+Write a script to create an array that represents the smaller element to the
+left of each corresponding index. If none found then use 0.
+
+Example 1
+
+Input: @A = (7, 8, 3, 12, 10)
+Output: (0, 7, 0, 3, 3)
+
+For index 0, the smallest number to the left of $A[0] i.e. 7 is none, so we put
+0.
+For index 1, the smallest number to the left of $A[1] as compare to 8, in (7) is
+7 so we put 7.
+For index 2, the smallest number to the left of $A[2] as compare to 3, in (7, 8)
+is none, so we put 0.
+For index 3, the smallest number to the left of $A[3] as compare to 12, in (7,
+8, 3) is 3, so we put 3.
+For index 4, the smallest number to the left of $A[4] as compare to 10, in (7,
+8, 3, 12) is 3, so we put 3 again.
+
+Example 2
+
+Input: @A = (4, 6, 5)
+Output: (0, 4, 4)
+
+For index 0, the smallest number to the left of $A[0] is none, so we put 0.
+For index 1, the smallest number to the left of $A[1] as compare to 6, in (4) is
+4, so we put 4.
+For index 2, the smallest number to the left of $A[2] as compare to 5, in (4, 6)
+is 4, so we put 4 again.
+
+=cut
+################################################################################
+
+#--------------------------------------#
+# Copyright © 2020 PerlMonk Athanasius #
+#--------------------------------------#
+
+use strict;
+use warnings;
+use Const::Fast;                    # Exports const()
+use Regexp::Common qw( number );    # Exports %RE
+
+const my $USAGE =>
+"Usage:
+  perl $0 [<A> ...]
+
+    [<A> ...]    Sequence of one or more integers\n";
+
+#-------------------------------------------------------------------------------
+BEGIN
+#-------------------------------------------------------------------------------
+{
+    $| = 1;
+    print "\nChallenge 073, Task #2: Smallest Neighbour (Perl)\n\n";
+}
+
+#===============================================================================
+MAIN:
+#===============================================================================
+{
+    my @A   = parse_command_line();
+    my @out = (0);              # The first element has no left-hand neighbours
+                                #   and so is always 0
+    my $min = $A[0];            # In the loop below, $min contains the smallest
+                                #   of the elements with index 0 .. $i-1
+
+    # For each element $A[$i] after the first: record the minimum of the ele-
+    # ments with index 0..$i-1 IFF that minimum is less than $A[$i]; otherwise,
+    # record 0
+
+    for my $i (1 .. $#A)
+    {
+        my $current = $A[$i];
+
+        push @out, $min < $current ? $min : 0;
+
+        $min = $current if $current < $min;     # Update $min for next iteration
+    }
+
+    print_arrays(\@A, \@out);
+}
+
+#-------------------------------------------------------------------------------
+sub parse_command_line
+#-------------------------------------------------------------------------------
+{
+    scalar @ARGV > 0         or die $USAGE;
+
+    / \A $RE{num}{int} \z /x or die $USAGE for @ARGV;
+
+    return @ARGV;
+}
+
+#-------------------------------------------------------------------------------
+sub print_arrays
+#-------------------------------------------------------------------------------
+{
+    my ($input, $output) = @_;
+    my  @widths;
+
+    # Calculate the print width for each element to facilitate vertical align-
+    # ment of corresponding elements in the input and output sequences 
+
+    for my $i (0 .. $#$input)
+    {
+        my $len_in  = length $input ->[$i];
+        my $len_out = length $output->[$i];
+
+        push @widths, $len_in > $len_out ? $len_in : $len_out;
+    }
+
+    # Print the input and output sequences
+
+    for my $args (['Input: @A =', $input ],
+                  ['Output:',     $output])
+    {
+        my $array = $args->[1];
+
+        printf "%-11s (%s)\n",
+                $args->[0], 
+                join ', ', map
+                           {
+                               sprintf '%*d', $widths[$_], $array->[$_]
+
+                           } 0 .. $#$array;
+    }
+}
+
+################################################################################
diff --git a/challenge-073/athanasius/raku/ch-1.raku b/challenge-073/athanasius/raku/ch-1.raku
new file mode 100644
index 0000000000..52526279a3
--- /dev/null
+++ b/challenge-073/athanasius/raku/ch-1.raku
@@ -0,0 +1,78 @@
+use v6d;
+
+################################################################################
+=begin comment
+
+Perl Weekly Challenge 073
+=========================
+
+Task #1
+-------
+*Min Sliding Window*
+
+Submitted by: Mohammad S Anwar
+
+You are given an array of integers @A and sliding window size $S.
+
+Write a script to create an array of min from each sliding window.
+
+Example
+
+Input: @A = (1, 5, 0, 2, 9, 3, 7, 6, 4, 8) and $S = 3
+Output: (0, 0, 0, 2, 3, 3, 4, 4)
+
+[(1 5 0) 2 9 3 7 6 4 8] = Min (0)
+[1 (5 0 2) 9 3 7 6 4 8] = Min (0)
+[1 5 (0 2 9) 3 7 6 4 8] = Min (0)
+[1 5 0 (2 9 3) 7 6 4 8] = Min (2)
+[1 5 0 2 (9 3 7) 6 4 8] = Min (3)
+[1 5 0 2 9 (3 7 6) 4 8] = Min (3)
+[1 5 0 2 9 3 (7 6 4) 8] = Min (4)
+[1 5 0 2 9 3 7 (6 4 8)] = Min (4)
+
+=end comment
+################################################################################
+
+#--------------------------------------#
+# Copyright © 2020 PerlMonk Athanasius #
+#--------------------------------------#
+
+subset Natural of UInt where * > 0;
+
+#-------------------------------------------------------------------------------
+BEGIN
+#-------------------------------------------------------------------------------
+{
+    "\nChallenge 073, Task #1: Min Sliding Window (Raku)\n".put;
+}
+
+#===============================================================================
+sub MAIN
+(
+    Natural:D :$S,                #= Sliding window size: 0 < S <= integers in A
+
+    *@A where { @A.elems >  0  &&            #= Sequence of one or more integers
+                @A.elems >= $S &&
+                @A.all   ~~ Int:D }
+)
+#===============================================================================
+{
+    "Input: @A = (%s) and \$S = %d\n".printf: @A.join(', '), $S;
+
+    my Int @minima;
+           @minima.push: min @A[$_ .. $_ + $S - 1] for 0 .. @A.elems - $S;
+
+    "Output: (%s)\n".printf: @minima.join: ', ';
+}
+
+#-------------------------------------------------------------------------------
+sub USAGE()
+#-------------------------------------------------------------------------------
+{
+    my Str $usage = $*USAGE;
+
+    $usage ~~ s/ ($*PROGRAM-NAME) /raku $0/;
+    $usage.put;
+}
+
+################################################################################
diff --git a/challenge-073/athanasius/raku/ch-2.raku b/challenge-073/athanasius/raku/ch-2.raku
new file mode 100644
index 0000000000..df2f74d872
--- /dev/null
+++ b/challenge-073/athanasius/raku/ch-2.raku
@@ -0,0 +1,131 @@
+use v6d;
+
+################################################################################
+=begin comment
+
+Perl Weekly Challenge 073
+=========================
+
+Task #2
+-------
+*Smallest Neighbour*
+
+Submitted by: Mohammad S Anwar
+
+You are given an array of integers @A.
+
+Write a script to create an array that represents the smaller element to the
+left of each corresponding index. If none found then use 0.
+
+Example 1
+
+Input: @A = (7, 8, 3, 12, 10)
+Output: (0, 7, 0, 3, 3)
+
+For index 0, the smallest number to the left of $A[0] i.e. 7 is none, so we put
+0.
+For index 1, the smallest number to the left of $A[1] as compare to 8, in (7) is
+7 so we put 7.
+For index 2, the smallest number to the left of $A[2] as compare to 3, in (7, 8)
+is none, so we put 0.
+For index 3, the smallest number to the left of $A[3] as compare to 12, in (7,
+8, 3) is 3, so we put 3.
+For index 4, the smallest number to the left of $A[4] as compare to 10, in (7,
+8, 3, 12) is 3, so we put 3 again.
+
+Example 2
+
+Input: @A = (4, 6, 5)
+Output: (0, 4, 4)
+
+For index 0, the smallest number to the left of $A[0] is none, so we put 0.
+For index 1, the smallest number to the left of $A[1] as compare to 6, in (4) is
+4, so we put 4.
+For index 2, the smallest number to the left of $A[2] as compare to 5, in (4, 6)
+is 4, so we put 4 again.
+
+=end comment
+################################################################################
+
+#--------------------------------------#
+# Copyright © 2020 PerlMonk Athanasius #
+#--------------------------------------#
+
+#-------------------------------------------------------------------------------
+BEGIN
+#-------------------------------------------------------------------------------
+{
+    "\nChallenge 073, Task #2: Smallest Neighbour (Raku)\n".put;
+}
+
+#===============================================================================
+sub MAIN
+(
+    *@A where { @A.elems >  0  &&            #= Sequence of one or more integers
+                @A.all   ~~ Int:D }
+)
+#===============================================================================
+{
+    my Int @out = (0);          # The first element has no left-hand neighbours
+                                #   and so is always 0
+    my Int $min = @A[0];        # In the loop below, $min contains the smallest
+                                #   of the elements with index 0 .. $i-1
+
+    # For each element @A[$i] after the first: record the minimum of the ele-
+    # ments with index 0..$i-1 IFF that minimum is less than @A[$i]; otherwise,
+    # record 0
+
+    for 1 .. @A.end -> UInt $i
+    {
+        my Int $current = @A[$i];
+
+        @out.push: $min < $current ?? $min !! 0;
+
+        $min = $current if $current < $min;     # Update $min for next iteration
+    }
+
+    print-arrays(@A, @out);
+}
+
+#-------------------------------------------------------------------------------
+sub USAGE()
+#-------------------------------------------------------------------------------
+{
+    my Str $usage = $*USAGE;
+
+    $usage ~~ s/ ($*PROGRAM-NAME) /raku $0/;
+    $usage.put;
+}
+
+#-------------------------------------------------------------------------------
+sub print-arrays(Array:D[Int:D] $input, Array:D[Int:D] $output)
+#-------------------------------------------------------------------------------
+{
+    my UInt @widths;
+
+    # Calculate the print width for each element to facilitate vertical align-
+    # ment of corresponding elements in the input and output sequences 
+
+    for 0 .. $input.end -> UInt $i
+    {
+        my $len_in  =  $input[$i].chars;
+        my $len_out = $output[$i].chars;
+
+        @widths.push: $len_in > $len_out ?? $len_in !! $len_out;
+    }
+
+    # Print the input and output sequences
+
+    for ['Input: @A =', $input ],
+        ['Output:',     $output] -> @args
+    {
+        my @array = @args[1].list;
+
+        "%-11s (%s)\n".printf:
+            @args[0],
+           (0 .. @array.end).map( { '%*d'.sprintf: @widths[$_], @array[$_] } )
+                            .join: ', ';
+    }
+}
+
+################################################################################