Changed strategy for task 2

1 files changed, 11 insertions, 16 deletions

diff --git a/challenge-209/wlmb/perl/ch-2.pl b/challenge-209/wlmb/perl/ch-2.pl
index e11b229f2c..46ad3198c8 100755
--- a/challenge-209/wlmb/perl/ch-2.pl
+++ b/challenge-209/wlmb/perl/ch-2.pl
@@ -5,25 +5,20 @@
 # See https://wlmb.github.io/2023/03/20/PWC209/#task-2-merge-account
 use v5.36;
 use English;
-my %merge_to;
 my %line_of;
 my @names;
 while(<>){
     chomp;
     my ($name, @addresses)=split / /;
-    $names[$INPUT_LINE_NUMBER] = $name;
-    $merge_to{$INPUT_LINE_NUMBER}=$INPUT_LINE_NUMBER; # merge to itself
-    for(@addresses){
-	my $l=$line_of{$_};
-	$line_of{$_}=$INPUT_LINE_NUMBER;
-        # merge overlapping accounts with current one
-	$merge_to{$l}=$merge_to{$merge_to{$l}}=$INPUT_LINE_NUMBER if defined $l;
-    }
+    next unless $name; # skip empty lines
+    $names[$INPUT_LINE_NUMBER]=$name;
+    my ($merged)=grep {defined $_} map {$line_of{$_}} @addresses;
+    $merged//=$INPUT_LINE_NUMBER; # current line by default
+    @line_of{@addresses}=($merged) x @addresses;
 }
-my @addresses = keys %line_of;                    # distinct addresses
-my %merged;                                       # merged accounts
-push @{$merged{$merge_to{$line_of{$_}}}}, $_      # add addresses to merged accounts
-    for @addresses;
-# output account name, (one of its) line number(s), addresses
-say join " ", $names[$_], "($_):", sort {$a cmp $b} @{$merged{$_}}
-    for sort {$names[$a] cmp $names[$b] || $a <=> $b} keys %merged;
+my %accounts;
+push @{$accounts{$line_of{$_}}}, $_ for(keys %line_of);
+# Sort output by account name and line number, and sort addresses
+say "$names[$_] ($_): ", join " ",
+    sort {$a cmp $b} @{$accounts{$_}}
+    for sort {$names[$a] cmp $names[$b] || $a <=>$b} keys %accounts;