4 files changed, 120 insertions, 0 deletions
diff --git a/challenge-068/paulo-custodio/Makefile b/challenge-068/paulo-custodio/Makefile
new file mode 100644
index 0000000000..ba9a2bf399
--- /dev/null
+++ b/challenge-068/paulo-custodio/Makefile
@@ -0,0 +1,3 @@
+all:
+	perl perl/ch-1.pl
+	perl perl/ch-2.pl
diff --git a/challenge-068/paulo-custodio/README b/challenge-068/paulo-custodio/README
new file mode 100644
index 0000000000..87dc0b2fbd
--- /dev/null
+++ b/challenge-068/paulo-custodio/README
@@ -0,0 +1 @@
+Solution by Paulo Custodio
diff --git a/challenge-068/paulo-custodio/perl/ch-1.pl b/challenge-068/paulo-custodio/perl/ch-1.pl
new file mode 100644
index 0000000000..e7279cec76
--- /dev/null
+++ b/challenge-068/paulo-custodio/perl/ch-1.pl
@@ -0,0 +1,77 @@
+#!/usr/bin/env perl
+
+# Challenge 068
+#
+# TASK #1 › Zero Matrix
+# Submitted by: Mohammad S Anwar
+# You are given a matrix of size M x N having only 0s and 1s.
+#
+# Write a script to set the entire row and column to 0 if an element is 0.
+#
+# Example 1
+# Input: [1, 0, 1]
+#        [1, 1, 1]
+#        [1, 1, 1]
+#
+# Output: [0, 0, 0]
+#         [1, 0, 1]
+#         [1, 0, 1]
+# Example 2
+# Input: [1, 0, 1]
+#        [1, 1, 1]
+#        [1, 0, 1]
+#
+# Output: [0, 0, 0]
+#         [1, 0, 1]
+#         [0, 0, 0]
+
+use Modern::Perl;
+use Clone 'clone';
+use Test::More;
+
+is_deeply [zero_matrix([1,0,1],
+                       [1,1,1],
+                       [1,1,1])],
+    [[0,0,0],
+     [1,0,1],
+     [1,0,1]];
+
+is_deeply [zero_matrix([1,0,1],
+                       [1,1,1],
+                       [1,0,1])],
+    [[0,0,0],
+     [1,0,1],
+     [0,0,0]];
+
+done_testing;
+
+
+sub zero_matrix {
+    my(@m) = @_;
+    my $orig = clone(\@m);
+    for my $r (0 .. @m-1) {
+        for my $c (0 .. @{$m[0]}-1) {
+            if (!$orig->[$r][$c]) {
+                @m = zero_row($r, @m);
+                @m = zero_col($c, @m);
+            }
+        }
+    }
+    return @m;
+}
+
+sub zero_row {
+    my($r, @m) = @_;
+    for my $c (0 .. @{$m[0]}-1) {
+        $m[$r][$c] = 0;
+    }
+    return @m;
+}
+
+sub zero_col {
+    my($c, @m) = @_;
+    for my $r (0 .. @m-1) {
+        $m[$r][$c] = 0;
+    }
+    return @m;
+}
diff --git a/challenge-068/paulo-custodio/perl/ch-2.pl b/challenge-068/paulo-custodio/perl/ch-2.pl
new file mode 100644
index 0000000000..b4730ddce8
--- /dev/null
+++ b/challenge-068/paulo-custodio/perl/ch-2.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/env perl
+
+# Challenge 068
+#
+# TASK #2 › Reorder List
+# Submitted by: Mohammad S Anwar
+# You are given a singly linked list $L as below:
+#
+# L0 ?  L1 ?  … ?  Ln-1 ?  Ln
+# Write a script to reorder list as below:
+#
+# L0 ?  Ln ?  L1 ?  Ln-1 ?  L2 ?  Ln-2 ?
+# You are ONLY allowed to do this in-place without altering the nodes’ values.
+#
+# Example
+# Input:  1 ?  2 ?  3 ?  4
+# Output: 1 ?  4 ?  2 ?  3
+
+use Modern::Perl;
+use Test::More;
+
+is_deeply reorder_list([1,[2,[3,[4]]]]), [1,[4,[2,[3]]]];
+done_testing;
+
+sub reorder_list {
+    my($l) = @_;
+    # get second element
+    my $tail = $l->[1];
+    # get and remove last element
+    my $p = $tail;
+    my $last;
+    while ($p->[1]) {
+        $last = $p;
+        $p = $p->[1];
+    }
+    my $eln = pop(@{$last});
+
+    return [$l->[0], [$eln->[0], $tail]];
+}