2 files changed, 78 insertions, 0 deletions
diff --git a/challenge-082/cheok-yin-fung/perl/ch-1.pl b/challenge-082/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..793642231d
--- /dev/null
+++ b/challenge-082/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+die "I need two positive integers!" if !$ARGV[1];
+
+sub gcd{              #Euclidean Algorithm
+    my $a = $_[0];
+    my $b = $_[1];
+
+    my $c = $a % $b;
+
+    if ($c == 0) {
+        return $b;
+    } 
+    else {
+        gcd($b,$c);
+    }
+}
+
+#all common factors of $a, $b are factors of its greatest common factor
+print join " ", grep { gcd($ARGV[0],$ARGV[1]) % $_ == 0} 1..$ARGV[0];
+print "\n";
diff --git a/challenge-082/cheok-yin-fung/perl/ch-2.pl b/challenge-082/cheok-yin-fung/perl/ch-2.pl
new file mode 100644
index 0000000000..5d2f8cc70b
--- /dev/null
+++ b/challenge-082/cheok-yin-fung/perl/ch-2.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+use Test::More tests => 6;
+
+sub interleave {
+    return 
+       interleave_one_side($_[0], $_[1], $_[2]) 
+        ||
+       interleave_one_side($_[1], $_[0], $_[2]) 
+}
+
+sub interleave_one_side {
+    my $A = $_[0];
+    my $B = $_[1];
+    my $C;
+    my $possibleinterleave = undef;
+    my $pos_AinC = 0;
+    do {
+        $C = $_[2];      #effect of substr modify $C 
+        $pos_AinC = index($C,$A,$pos_AinC);
+        if ($pos_AinC != -1) {
+            substr($C, $pos_AinC, length $A, "");
+            if ($C eq $B) {
+                $possibleinterleave = 1;
+            } 
+            else {
+                $pos_AinC++;
+            }
+        }
+    } while ($pos_AinC != -1  and
+                $pos_AinC < length($C) and
+                !$possibleinterleave);
+    return $possibleinterleave;
+}
+
+if ($ARGV[2]) {
+    if (interleave($ARGV[0], $ARGV[1], $ARGV[2])) {
+        print 1, "\n";
+    }
+    else {
+        print -1, "\n";
+    }
+} 
+else {
+    die "I need three input parameters."
+}
+
+
+ok interleave("XY", "X", "XXY"), "example 1";
+ok interleave("XXY", "XXZ", "XXXXZY"), "example 2";
+ok !interleave("YX", "X", "XXY"), "example 3";
+ok interleave("alpha", "beta", "alphabeta"), "alphabeta";
+ok interleave("alphabeta", "alpha", "alphabealphata"), "alphabealphata";
+ok interleave("abcd", "ab", "abcabd"), "a..b";