Solution to task 2

1 files changed, 62 insertions, 0 deletions

diff --git a/challenge-208/jo-37/perl/ch-2.pl b/challenge-208/jo-37/perl/ch-2.pl
new file mode 100755
index 0000000000..723db1de46
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+++ b/challenge-208/jo-37/perl/ch-2.pl
@@ -0,0 +1,62 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use List::Util qw(uniqint sum);
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [N...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+N...
+    list of numbers
+
+EOS
+
+
+### Input and Output
+
+main: {
+    my ($dup, $miss) = dup_miss(@ARGV);
+    say $dup || $miss ? "($dup,$miss)" : -1;
+}
+
+
+### Implementation
+
+sub dup_miss {
+    # - A single duplicate value is the difference between the sum over
+    #   all elements and the sum over the unique elements.
+    # - A single missing value is the difference between the sum over
+    #   all expected elements and the sum over the unique elements.
+    my $usum = sum uniqint @_;
+    map $_ - $usum, sum(@_), @_ * (@_ + 1) / 2;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+        is [dup_miss(1, 2, 2, 4)], [2, 3], 'example 1';
+        is [dup_miss(1, 2, 3, 4)], [0, 0], 'example 2';
+        is [dup_miss(1, 2, 3, 3)], [3, 4], 'example 3';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}