Solutions to challenge 217

2 files changed, 124 insertions, 0 deletions

diff --git a/challenge-217/jo-37/perl/ch-1.pl b/challenge-217/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..4c43a4b8ca
--- /dev/null
+++ b/challenge-217/jo-37/perl/ch-1.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/perl -s
+
+use v5.24;
+use Test2::V0 '!float';
+use PDL;
+use PDL::NiceSlice;
+use experimental 'signatures';
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [-verbose] [--] [M...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+M...
+    a matrix in any form accepted by the PDL string contructor, e.g.
+    "[1 2 3][4 5 6]"
+
+EOS
+
+
+### Input and Output
+
+say third_smallest(pdl "@ARGV");
+
+
+### Implementation
+
+# There is no need to sort the matrix.  Just pick the third smallest
+# value's index and return the value.
+sub third_smallest ($p) {
+    minimum_n_ind $p->flat, my $min = zeroes indx, 3;
+    $p->flat->($min(-1))->sclr;
+}
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is third_smallest(pdl([3, 1, 2], [5, 2, 4], [0, 1, 3])), 1,
+        'example 1';
+        
+        is third_smallest(pdl([2, 1], [4, 5])), 4,
+        'example 2';
+
+        is third_smallest(pdl([1, 0, 3], [0, 0, 0], [1, 2, 1])), 0,
+        'example 3';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}
diff --git a/challenge-217/jo-37/perl/ch-2.pl b/challenge-217/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..f6145ffd7b
--- /dev/null
+++ b/challenge-217/jo-37/perl/ch-2.pl
@@ -0,0 +1,59 @@
+#!/usr/bin/perl -s
+
+use v5.24;
+use Test2::V0;
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [N...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N...
+    list of numbers
+
+EOS
+
+
+### Input and Output
+
+say maximum_number(@ARGV);
+
+
+### Implementation
+
+# At first glance it looks as the reverse lexicographic order would
+# solve the task, but this is disproved by example 5.  Thus creating a
+# "reverse concatenation order".
+sub maximum_number {
+    join '', sort {$b . $a <=> $a . $b} @_;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is maximum_number(1, 23), 231, 'example 1';
+        is maximum_number(10, 3, 2), 3210, 'example 2';
+        is maximum_number(31, 2, 4, 10), 431210, 'example 3';
+        is maximum_number(5, 11, 4, 1, 2), 542111, 'example 4';
+        is maximum_number(1, 10), 110, 'example 5';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}