Added Solution by Myoungjin Jeon

3 files changed, 237 insertions, 0 deletions

diff --git a/challenge-068/jeongoon/README b/challenge-068/jeongoon/README
new file mode 100644
index 0000000000..fb69b53165
--- /dev/null
+++ b/challenge-068/jeongoon/README
@@ -0,0 +1 @@
+Solution by Myoungjin Jeon
diff --git a/challenge-068/jeongoon/perl/ch-1.pl b/challenge-068/jeongoon/perl/ch-1.pl
new file mode 100644
index 0000000000..9e9df746c2
--- /dev/null
+++ b/challenge-068/jeongoon/perl/ch-1.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/env perl
+use strict; use warnings;
+
+sub read_row_ {
+    my @buffer = @{$_[0]};
+    my $line = <STDIN>;
+    chomp $line if defined $line;
+    push @buffer, $line;
+}
+
+sub get_row_ {
+    my $buffer = $_[0];
+    shift @{$buffer};
+}
+
+my @row_raw;
+my $round = 1;
+my $use_example;
+
+if ( $use_example = !!( grep { /^--use-example$/ } @ARGV) ) {
+    $round = 2;
+    @row_raw = ( "[1, 0, 1]", "[1, 1, 1]", "[1, 1, 1]", undef,
+                 "[1, 0, 1]", "[1, 1, 1]", "[1, 0, 1]", undef );
+
+}
+
+# initial value
+{
+    my ( @row_whole_zero_flag,  $row_some_zero_str );
+
+    read_row_( \@row_raw ) unless $use_example;
+    ( $row_some_zero_str = $row_raw[0] ) =~ s/0/1/g;
+
+    while ( defined( my $r_raw = get_row_( \@row_raw) ) ) {
+        my $new_row_some_zero_str = $row_some_zero_str & $r_raw;
+        push @row_whole_zero_flag, !!( index( $r_raw, "0" ) > 0 );
+        $row_some_zero_str = $new_row_some_zero_str;
+        read_row_( \@row_raw ) unless $use_example;
+    }
+
+    ( my $row_whole_zero_str = $row_some_zero_str ) =~ s/1/0/g;
+
+    print( ( $_ ? $row_whole_zero_str : $row_some_zero_str ).$/ )
+      for @row_whole_zero_flag;
+    print $/;
+    redo if ( --$round ) > 0;
+}
diff --git a/challenge-068/jeongoon/perl/ch-2.pl b/challenge-068/jeongoon/perl/ch-2.pl
new file mode 100644
index 0000000000..4e6cae84c4
--- /dev/null
+++ b/challenge-068/jeongoon/perl/ch-2.pl
@@ -0,0 +1,189 @@
+#!/usr/bin/env perl
+use utf8;
+use open ':std', ':encoding(UTF-8)';
+use strict; use warnings;
+
+BEGIN {
+    $::debugging = 0;
+    if ( grep { /^--debug$/ } @ARGV ) {
+        $::debugging = 1;
+    }
+
+    our $dprint = sub( @ ) {
+        ++$|;
+        print "[DEBUG] ",@_;
+    };
+
+    *::dprint = $::debugging ? $dprint : sub {};
+}
+
+package linked_list;
+use Scalar::Util qw(blessed refaddr weaken);
+#use namespace::clean;
+
+sub new {
+    my $class = shift;
+    my $obj   = {};
+    $obj->{beg_itr_} = linked_list::iterator->new();
+    return bless $obj, ( blessed $class || $class );
+}
+
+sub DESTROY {
+    my $itr = $_[0]->itr;
+    {
+        my $rubbish = $itr->pop_back;
+        if ( defined $rubbish ) {
+            ::dprint "removing: " . $rubbish.$/;
+            undef $rubbish;
+            redo;
+        }
+
+    }
+
+    ::dprint "and remvoing: " .$_[0]->{beg_itr_}.$/;
+    undef $_[0]->{beg_itr_};
+}
+
+sub itr   { $_[0]->{beg_itr_} }
+
+sub count {
+    my $itr = $_[0]->itr;
+
+    my $count = 0;
+    while ( defined $itr ) {
+        ++$count;
+        $itr = $itr->next_itr;
+    }
+    $count;
+}
+
+sub last_itr {
+    my $itr = $_[0]->itr;
+    return undef unless defined $itr;
+    while ( defined $itr->next_itr ) {
+        $itr = $itr->next_itr;
+    }
+    return $itr;
+}
+
+package linked_list::iterator;
+use Scalar::Util qw(blessed refaddr weaken isweak);
+
+sub new {
+    my $class = shift;
+    my $value  = shift;
+    my $obj   = [ $value, undef ];
+
+    weaken( $obj->[0] ) if refaddr( $obj->[0] );
+    bless $obj, ( blessed $class || $class );
+}
+
+sub next_itr   () { $_[0]->[1]; }
+sub value      () { $_[0]->[0]; }
+
+sub push_back_value ( $ ) {
+    if ( not defined $_[0]->[0] and not defined $_[0]->[1] ) {
+        # first iterator
+        $_[0]->[0] = $_[1];
+        weaken( $_[0]->[0] ) if refaddr ( $_[0]->[0] );
+        return 1;
+    }
+
+    my $new = linked_list::iterator->new( $_[1] );
+    my $nxt = $_[0]->[1]; # $_[0]->next_itr
+    $_[0]->[1] = $new;
+    $new->[1]  = $nxt;
+    1;
+}
+
+sub push_back ( $ ) {
+    my $friend_class = blessed( $_[1] );
+    if ( not defined $friend_class
+         or
+         not $friend_class->isa( __PACKAGE__ ) ) {
+        ::dprint "friend is not a valid iterator\n";
+        return 0;
+    }
+    if ( blessed $_[1]->[1] ) {
+        ::dprint "friend already has another friend: use poped iterator only";
+        return 0;
+    }
+    $_[1]->[1] = $_[0]->[1];
+    $_[0]->[1] = $_[1];
+    return 1;
+}
+
+sub pop_back  () {
+    if ( not defined $_[0]->[1] ) {
+        return undef;
+    }
+    my $togo = $_[0]->[1];
+    $_[0]->[1] = $togo->[1];
+    $togo->[1] = undef;
+    return $togo;
+}
+
+sub DESTROY {
+    ::dprint "$_[0]: destroyed!!!\n";
+}
+
+package main;
+
+sub print_all_values ($) {
+    my $itr = shift;
+    print $itr->value;
+    while ( $itr = $itr->next_itr ) {
+        print " → ".$itr->value;
+    }
+    print "\n";
+}
+
+my @example = 1..6;
+my $L = linked_list->new();
+my $itr = $L->itr;
+for my $value ( @example ) {
+    $itr->push_back_value( $value );
+    $itr = $itr->next_itr || $L->itr; # ugly
+}
+
+$itr = $L->itr;
+
+::dprint "input:\n";
+print_all_values( $itr ) if $::debugging;
+
+my $count = $L->count;
+::dprint "count of list: $count\n";
+
+
+my $pair_left_num  = 1;
+my $pair_left_pos  = 0;
+my $pair_right_num = $count - $pair_left_num + 1;
+my $pair_right_pos = $pair_left_pos + 1;
+
+my $l_itr = $L->itr;
+
+while ( ( $pair_right_pos + 1 ) < $pair_right_num ) {
+    my $r2_itr = $l_itr; # 2nd last iterator
+
+    my $n_repeat = $pair_right_num - 1 - $pair_left_pos;
+    ::dprint "from: $pair_left_pos, go next $n_repeat time(s) to find 2nd last iterator.\n";
+    while ( --$n_repeat > 0 ) {  # find (N-1)th node
+         $r2_itr = $r2_itr->next_itr;
+    }
+    my $r_itr = $r2_itr->pop_back;
+    ::dprint "right of the pair has value of: ".$r_itr->value.$/;
+    $l_itr->push_back( $r_itr );
+
+    $l_itr = $l_itr->next_itr->next_itr;
+
+    ++$pair_left_num;
+    $pair_left_pos += 2;
+    --$pair_right_num;
+    $pair_right_pos = ( $pair_left_pos + 1 );
+}
+
+undef $l_itr;
+$itr = $L->itr;
+
+::dprint "output:\n";
+print_all_values( $itr );