merging Listy module and ch-1.pl

1 files changed, 58 insertions, 18 deletions

diff --git a/challenge-059/sangeet-kar/perl/ch-1.pl b/challenge-059/sangeet-kar/perl/ch-1.pl
index 31586ff9ec..f6154d9d92 100644
--- a/challenge-059/sangeet-kar/perl/ch-1.pl
+++ b/challenge-059/sangeet-kar/perl/ch-1.pl
@@ -1,47 +1,87 @@
 use strict;
 use warnings;
-use File::Basename;
-use lib dirname (__FILE__);
 use experimental qw(signatures);
 
-use Listy;
+#List node class
+package Node;
 
-sub find_parent ($lst, $node, $start_node=undef) {
-    $start_node //= $lst->{head};
+sub new ($class, $val, $next_node=undef) {
+    bless {val => $val, next_node => $next_node}, $class;
+}
+
+#LinkedList class
+package Listy;
+
+sub new ($class, $list) {
+    my $head = my $last = undef;
+
+    for (@$list) {
+        my $node = Node->new ($_);
+        if (defined $last) {
+            $last->{next_node} = $node;
+            $last = $node;
+        }
+        else {
+            $head = $last = $node;
+        }        
+    }
+    bless {head => $head, last1 => $last}, $class
+}
+
+sub is_empty ($self) {
+    not defined $self->{head};
+}
+
+sub print_list ($self) {
+    if ($self->is_empty) {
+        print "empty";
+    }
+    else {
+        for (my $i = $self->{head}; defined $i; $i = $i->{next_node}) {
+            print $i->{val};
+            print "->" unless $i == $self->{last1};
+        }
+    }
+}
+
+sub parent_of_node ($self, $node, $start_node=undef) {
+    $start_node //= $self->{head};
     return $start_node if $start_node == $node;
     
     $start_node = $start_node->{next_node} while $start_node->{next_node} != $node;
     return $start_node;
 }
 
-sub shift_list ($lst, $i, $j) {
-    my $parent_i = find_parent $lst, $i;
-    my $parent_j = find_parent $lst, $j, $i;
+sub rotate_right_to_left ($self, $i, $j) {
+    my $parent_i = $self->parent_of_node($i);
+    my $parent_j = $self->parent_of_node($j, $i);
 
     $parent_j->{next_node} = $j->{next_node};
-    $lst->{last1} = $parent_j if $j == $lst->{last1};
+    $self->{last1} = $parent_j if $j == $self->{last1};
     $j->{next_node} = $i;
     if ($parent_i == $i) {
-        $lst->{head} = $j;
+        $self->{head} = $j;
     }
     else {
         $parent_i->{next_node} = $j;
     }
 }
 
-sub partition_list {
-    my ($lst, $k) = @_;
-    my $i = $lst->{head};
+sub partition ($self, $k) {
+    my $i = $self->{head};
     $i = $i->{next_node} if defined $i && $i->{val} < $k;
-    return $lst unless defined $i;
+    return unless defined $i;
     
     while (1) {
         my $j = $i->{next_node};
         $j = $j->{next_node} while defined $j && $j->{val} >= $k;
-        return $lst unless defined $j;
-        shift_list($lst, $i, $j);
+        return unless defined $j;
+        $self->rotate_right_to_left($i, $j);
     }
 }
 
-my $lst = Listy->new ([1, 4, 3, 2, 5, 2]);
-partition_list ($lst, 3) -> print_list;
+__END__
+
+my $list = Listy->new ([1, 4, 3, 2, 5, 2]);
+$list->partition(3);
+$list->print_list;
\ No newline at end of file