Add validatation for task 1

1 files changed, 24 insertions, 1 deletions

diff --git a/challenge-268/bob-lied/perl/ch-1.pl b/challenge-268/bob-lied/perl/ch-1.pl
index e4512bc29d..faaffefebc 100644
--- a/challenge-268/bob-lied/perl/ch-1.pl
+++ b/challenge-268/bob-lied/perl/ch-1.pl
@@ -28,13 +28,32 @@ use Getopt::Long;
 my $Verbose = 0;
 my $DoTest  = 0;
 
+sub mn :prototype(\@@)
+{
+    my @x = @{shift @_};
+    my @y = @_;
+    say "x: (", join(",", @x), ")";
+    say "y: (", join(",", @y), ")";
+}
+my @x=(1,2); my @y=(3,4);
+mn(@x, @y);
+
 GetOptions("test" => \$DoTest, "verbose" => \$Verbose);
 exit(!runTest()) if $DoTest;
 
+sub validate($x, $y, $magic)
+{
+    return undef if $x->$#* != $y->$#*;
+    my %should_be_y;
+    $should_be_y{$_ + $magic} = $_ for $x->@*;
+    delete $should_be_y{$_} for $y->@*;
+    return scalar(%should_be_y) == 0 ? $magic : undef;
+}
+
 sub magicNumber($x, $y)
 {
     use List::Util qw/min/;
-    return min($y->@*) - min($x->@*);
+    return validate($x, $y, min($y->@*) - min($x->@*));
 }
 
 sub runTest
@@ -45,5 +64,9 @@ sub runTest
     is( magicNumber([1,2,1], [5,4,4]), 3, "Example 2");
     is( magicNumber([2    ], [5    ]), 3, "Example 3");
 
+    is( magicNumber([9    ], [8,7  ]), undef, "Different lengths");
+    is( magicNumber([9,6,4], [7,3,6]), undef, "No magic");
+    is( magicNumber([2,2,5], [4,4,7]), 2,     "With repeats");
+
     done_testing;
 }