Task 1 change to shortcut evaluation above and below

1 files changed, 29 insertions, 2 deletions

diff --git a/challenge-270/bob-lied/perl/ch-1.pl b/challenge-270/bob-lied/perl/ch-1.pl
index 5cbd51f959..84d9b14946 100644
--- a/challenge-270/bob-lied/perl/ch-1.pl
+++ b/challenge-270/bob-lied/perl/ch-1.pl
@@ -33,14 +33,27 @@ my $DoTest  = 0;
 GetOptions("test" => \$DoTest, "verbose" => \$Verbose);
 exit(!runTest()) if $DoTest;
 
+# Extract a column from a matrix
 sub columnOf($matrix, $col)
 {
     map { $_->[$col] } $matrix->@*;
 }
 
+# Extract the column above a row, not including the row
+sub above($matrix, $row, $col)
+{
+    map { $_->[$col] } $matrix->@[0 .. $row-1];
+}
+
+# Extract the column below a row, not including the row
+sub below($matrix, $row, $col)
+{
+    map { $_->[$col] } $matrix->@[$row+1 .. $matrix->$#*];
+}
+
 sub specialPos($matrix)
 {
-    use List::Util qw/sum/;
+    use List::Util qw/sum all/;
     use List::MoreUtils qw/indexes/;
 
     my $special = 0;
@@ -48,7 +61,10 @@ sub specialPos($matrix)
     for ( 0 .. $matrix->$#* )
     {
         my @ones = indexes { $_ == 1 } $matrix->[$_]->@*;
-        $special++ unless ( @ones != 1 ) || (sum columnOf($matrix, $ones[0]) ) != 1;
+
+        $special++ if ( @ones == 1 )
+                   && ( all { $_ == 0 } above($matrix, $_, $ones[0]) )
+                   && ( all { $_ == 0 } below($matrix, $_, $ones[0]) );
     }
 
     return $special;
@@ -59,6 +75,14 @@ sub runTest
     use Test2::V0;
 
     my $matrix = [ [1,0,0], [0,0,1], [1,0,0] ];
+    is( [ above($matrix, 0, 0) ], [], "Above 0,0");
+    is( [ above($matrix, 1, 0) ], [ 1 ], "Above 1,0");
+    is( [ above($matrix, 2, 0) ], [ 1, 0 ], "Above 2,0");
+    is( [ below($matrix, 0, 1) ], [ 0, 0 ], "Below 0,0");
+    is( [ below($matrix, 1, 1) ], [ 0 ], "Below 1,0");
+    is( [ below($matrix, 2, 1) ], [ ], "Below 2,0");
+    is( [ below($matrix, 2, 2) ], [ ], "Below 2,2");
+
     is( specialPos($matrix), 1, "Example 1");
 
     $matrix = [ [1,0,0], [0,1,0], [0,0,1] ];
@@ -73,6 +97,9 @@ sub runTest
     $matrix = [ [0,0], [1,0], [0,0], [1,1] ];
     is( specialPos($matrix), 0, "row > col");
 
+    $matrix = [ [0,0], [1,0], [0,0], [0,0] ];
+    is( specialPos($matrix), 1, "row > col, with special");
+
     $matrix = [ [1] ];
     is( specialPos($matrix), 1, "degenerate 1x1 with 1");