PWC 248 Task 2 complete

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+#!/usr/bin/env perl
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# Copyright (c) 2023, Bob Lied
+#=============================================================================
+#  
+# ch-2.pl Perl Weekly Challenge 248 Task 2 Submatrix Sum
+#=============================================================================
+# You are given a NxM matrix A of integers.
+# Write a script to construct a (N-1)x(M-1) matrix B having elements that
+# are the sum over the 2x2 submatrices of A,
+# b[i,k] = a[i,k] + a[i,k+1] + a[i+1,k] + a[i+1,k+1]
+# Example 1 Input: $a = [ [1,  2,  3,  4],
+#                         [5,  6,  7,  8],
+#                         [9, 10, 11, 12] ]
+#           Output: $b = [ [14, 18, 22],
+#                          [30, 34, 38] ]
+# Example 2 Input: $a = [ [1, 0, 0, 0],
+#                         [0, 1, 0, 0],
+#                         [0, 0, 1, 0],
+#                         [0, 0, 0, 1] ]
+#           Output: $b = [ [2, 1, 0],
+#                          [1, 2, 1],
+#                          [0, 1, 2] ]
+#=============================================================================
+
+use v5.38;
+
+use builtin qw/true false/; no warnings "experimental::builtin";
+
+use Getopt::Long;
+my $Verbose = 0;
+my $DoTest  = 0;
+
+GetOptions("test" => \$DoTest, "verbose" => \$Verbose);
+exit(!runTest()) if $DoTest;
+
+sub sms($m)
+{
+    my $height = $m->$#*;
+    my $width  = $m->[0]->$#*;
+
+    my @output;
+    push @output, [ (0) x $width ] for 0 .. $height -1;
+
+    for my $i (  0 .. $height-1 )
+    {
+        for my $k ( 0 .. $width-1 )
+        {
+            $output[$i][$k] = $m->[$i  ][$k] + $m->[$i  ][$k+1]
+                            + $m->[$i+1][$k] + $m->[$i+1][$k+1];
+        }
+    }
+    return \@output;
+}
+
+sub runTest
+{
+    use Test2::V0;
+
+    is( sms( [ [1,  2,  3,  4],
+               [5,  6,  7,  8],
+               [9, 10, 11, 12] ]),
+            [ [14, 18, 22], [30, 34, 38] ] , "Example 1");
+
+    is( sms( [ [1, 0, 0, 0],
+               [0, 1, 0, 0],
+               [0, 0, 1, 0],
+               [0, 0, 0, 1] ] ),
+            [ [2, 1, 0],
+              [1, 2, 1],
+              [0, 1, 2] ], "Example 2");
+
+    done_testing;
+}