From 7775ff4ca11d2be6ec6833e687af4cb3f3ea313e Mon Sep 17 00:00:00 2001
From: Jörg Sommrey <28217714+jo-37@users.noreply.github.com>
Date: Tue, 15 Jun 2021 08:35:19 +0200
Subject: Solution to task 1

---
 challenge-117/jo-37/perl/ch-1.pl | 139 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100755 challenge-117/jo-37/perl/ch-1.pl

diff --git a/challenge-117/jo-37/perl/ch-1.pl b/challenge-117/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..ad21fc4e73
--- /dev/null
+++ b/challenge-117/jo-37/perl/ch-1.pl
@@ -0,0 +1,139 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use warnings;
+use autodie;
+use experimental 'signatures';
+
+our ($tests, $examples, $rows);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV && $rows;
+usage: $0 [-examples] [-tests] [-rows=n filename]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-rows=n
+    expect n rows in the given file
+
+filename
+    filename containing numbered rows
+
+EOS
+
+
+### Input and Output
+
+say join "\n", @{find_missing_rows(*ARGV{IO}, $rows)};
+
+
+### Implementation
+
+# The task is certainly over-determined:
+# - There are 14 rows of data.
+# - It's stated that rows are numbered 1 to 15.
+# - It's stated that one row would be missing.
+# Either the specification of the number of missing rows or the desired
+# number of rows is superfluous.  Ignoring the number of missing rows
+# here.
+# Note: Ignoring both the number of rows *and* the number of missing
+# rows prevents the determination of a missing last row.
+sub find_missing_rows ($fh, $rows) {
+    my %rows;
+    @rows{1 .. $rows} = (1 .. $rows);
+    # Row numbers shall be separated with a comma from the rest of the
+    # row and may have leading zeros.
+    delete @rows{do {local $/; <$fh> =~ /^0*(\d+)(?=,)/mg}};
+
+    [sort {$a <=> $b} values %rows];
+}
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        open my $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            11, Line Eleven
+            1, Line one
+            9, Line Nine
+            13, Line Thirteen
+            2, Line two
+            6, Line Six
+            8, Line Eight
+            10, Line Ten
+            7, Line Seven
+            4, Line Four
+            14, Line Fourteen
+            3, Line three
+            15, Line Fifteen
+            5, Line Five
+EOS
+        is find_missing_rows($fh, 15), [12], 'example';
+        close $fh;
+
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        my $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            2, Line two
+            3, Line three
+EOS
+        is find_missing_rows($fh, 3), [1], 'missing first row';
+        close $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            1, Line one
+            2, Line two
+EOS
+        is find_missing_rows($fh, 3), [3], 'missing last row';
+        close $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            1, Line one
+            2, Line two
+            3, Line three
+EOS
+        is find_missing_rows($fh, 3), [], 'nothing missing';
+        close $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            01, Line one
+            02, Line two
+            03, Line three
+EOS
+        is find_missing_rows($fh, 3), [], 'leading zeros';
+        close $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            1, Line one
+            3, Line three
+            5, Line Five
+EOS
+        is find_missing_rows($fh, 5), [2, 4], 'multiple missing rows';
+        close $fh;
+
+        open $fh, '<', \(<<EOS =~ s/^ +//gmr);
+            1, Line one
+            2 Line two
+            3, Line three
+EOS
+        is find_missing_rows($fh, 3), [2], 'malformed line number';
+        close $fh;
+
+	}
+
+    done_testing;
+    exit;
+}
-- 
cgit