Further improvements to Robbie Hatley's Perl solutions for The Weekly Challenge #268.

2 files changed, 8 insertions, 6 deletions

diff --git a/challenge-268/robbie-hatley/perl/ch-1.pl b/challenge-268/robbie-hatley/perl/ch-1.pl
index 091a5abd38..ccf51e42d6 100755
--- a/challenge-268/robbie-hatley/perl/ch-1.pl
+++ b/challenge-268/robbie-hatley/perl/ch-1.pl
@@ -44,7 +44,6 @@ PROBLEM NOTES:
 I'll sort both arrays then subtract the second from the first. If all elements of the difference are the same,
 that common value is our "magic number", otherwise return "none":
 
-   # Determine "magic number" (if any) for given matrix:
    sub magic ($matref) {
       my @row1 = sort {$a<=>$b} @{$$matref[0]};
       my @row2 = sort {$a<=>$b} @{$$matref[1]};
diff --git a/challenge-268/robbie-hatley/perl/ch-2.pl b/challenge-268/robbie-hatley/perl/ch-2.pl
index b0c388f978..2e59faae33 100755
--- a/challenge-268/robbie-hatley/perl/ch-2.pl
+++ b/challenge-268/robbie-hatley/perl/ch-2.pl
@@ -37,10 +37,14 @@ PROBLEM NOTES:
 This is equivalent to first sorting each array in increasing numeric order ("sort {$a<=>$b} @array"), then
 swapping pairs. Something like this:
 
-   # Reorder array of ints into a zigzagging ascending stairway:
    sub stairway (@array) {
-      my @sorted = sort {$a<=>$b} @array;
-      map {@sorted[2*$_+1,2*$_]} 0..($#sorted-1)/2;
+      my @zigzag = sort {$a<=>$b} @array;
+      for ( my $i = 0 ; $i <= $#zigzag - 1 ; $i += 2 ) {
+         my $temp = $zigzag[$i];
+         $zigzag[$i] = $zigzag[$i+1];
+         $zigzag[$i+1] = $temp;
+      }
+      return @zigzag;
    }
 
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@@ -71,8 +75,7 @@ Output is to STDOUT and will be each input followed by the corresponding output.
 
    # Return stairway sort of an array:
    sub stairway (@array) {
-      my @sorted = sort {$a<=>$b} @array;
-      pairmap {$b,$a} @sorted;
+      pairmap {$b,$a} sort {$a<=>$b} @array;
    }
 
 # ------------------------------------------------------------------------------------------------------------