Solution to task 2

1 files changed, 109 insertions, 0 deletions

diff --git a/challenge-334/jo-37/perl/ch-2.pl b/challenge-334/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..51aa04f48b
--- /dev/null
+++ b/challenge-334/jo-37/perl/ch-2.pl
@@ -0,0 +1,109 @@
+#!/usr/bin/perl
+
+use v5.26;
+use Test2::V0 qw(!float -no_srand);
+use Test2::Tools::Subtest 'subtest_streamed';
+use Getopt::Long;
+use experimental 'signatures';
+
+use PDL;
+use PDL::NiceSlice;
+
+### Options and Arguments
+
+my ($tests, $examples, $verbose, $location);
+GetOptions(
+    'examples!' => \$examples,
+    'tests!'    => \$tests,
+    'verbose!'  => \$verbose,
+    'location=s' => \$location,
+) or usage();
+
+run_tests($examples, $tests);	# tests do not return
+
+usage() unless @ARGV && $location;
+
+sub usage {
+    die <<~EOS;
+    $0 - nearest valid point
+
+    usage: $0 [-examples] [-tests] [-location [X, Y,...] [X1, Y1,...]...]
+
+    -examples
+        run the examples from the challenge
+     
+    -tests
+        run some tests
+
+    -location [X,Y]
+        current location, e.g. [3,4] or 3,4
+
+    [X1,Y1,...]...
+        list of points
+        e.g.  [1,2] [3,1] [2,4] [2,3] or '1,2;3,1;2,4;2,3'
+    EOS
+}
+
+
+### Input and Output
+
+say nearest_valid_point($location, "@ARGV");
+
+
+### Implementation
+#
+# For details see:
+# https://github.sommrey.de/the-bears-den/2025/08/17/ch-334.html#task-2
+
+
+sub nearest_valid_point ($x, @points) {
+    my $d = abs pdl(@points) - pdl($x);
+    (my $valid = which !$d->minover)->isempty && return -1;
+    $valid($d(,$valid)->sumover->minimum_ind)->sclr;
+}
+
+
+### Examples and Tests
+
+sub run_tests ($examples, $tests) {
+    return unless $examples || $tests;
+
+    state sub run_example ($args, $expected, $name) {
+        my $result = nearest_valid_point(@$args);
+        is $result, $expected,
+            "$name: (@{[map qq([@$_]), @$args]}) -> $expected";
+    }
+
+    plan 2;
+
+    $examples ? subtest_streamed(examples => sub {
+        my @examples = (
+            [[[3, 4] ,=> ([1, 2], [3, 1], [2, 4], [2, 3])], 2, 'example 1'],
+            [[[2, 5] ,=> ([3, 4], [2, 3], [1, 5], [2, 5])], 3, 'example 2'],
+            [[[1, 1] ,=> ([2, 2], [3, 3], [4, 4])],        -1, 'example 3'],
+            [[[0, 0] ,=> ([0, 1], [1, 0], [0, 2], [2, 0])], 0, 'example 4'],
+            [[[5, 5] ,=> ([5, 6], [6, 5], [5, 4], [4, 5])], 0, 'example 5'],
+        );
+        plan scalar @examples;
+        for (@examples) {
+            run_example @$_;
+        }
+    }) : pass 'skip examples';
+
+    $tests ? subtest_streamed(tests => sub {
+        my @tests = (
+            [[[1, 1, 1] ,=> ([0, 0, 0])], -1, 'no point in 3-d'],
+            [[[1, 1, 1] ,=>
+                    ([0, 0, 0],
+                     [0, 0, 1], [0, 1, 0], [1, 0, 0],
+                     [1, 1, 0], [1, 0, 1], [0, 1, 1])],
+                4, 'cube'],
+        );
+        plan scalar @tests;
+        for (@tests) {
+            run_example @$_;
+        }
+    }) : pass 'skip tests';
+
+    exit;
+}