From 3f16527fb1c257355dc971ea8a1e26879aa73a86 Mon Sep 17 00:00:00 2001
From: Fung Cheok Yin <61836418+E7-87-83@users.noreply.github.com>
Date: Sun, 5 Jul 2020 22:37:14 +0800
Subject: Create ch-1.pl

---
 challenge-067/cheok-yin-fung/perl/ch-1.pl | 55 +++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 challenge-067/cheok-yin-fung/perl/ch-1.pl

diff --git a/challenge-067/cheok-yin-fung/perl/ch-1.pl b/challenge-067/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..92dfa05e71
--- /dev/null
+++ b/challenge-067/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+use strict;
+use Data::Dumper;
+
+# Usage:   ch-1.pl [m] [n (also size of the combinations)]
+# Main Idea: use the combinatorical identity  C(n-1,r)+C(n-1,r-1)==C(n,r)
+
+my $m = 5;
+my $n = 2;
+if ($ARGV[0] and $ARGV[1]) {
+    $m = $ARGV[0];
+    $n = $ARGV[1]; 
+}
+
+my @A =( [] , [[ []  ] ,[[1]]]  ,  [ [ []  ], [ [1],[2] ], [ [1,2] ]] );
+
+#my $x = Data::Dumper->new(\@A);    # lines for testing
+#print $x->Dump;
+#print "\n";
+
+
+my $i = 3;
+my $csize;     #the size of the combination(s)
+
+while ($i<=$m) {
+    $A[$i][0] = [];
+    my @tempA1 = map {[$_]} (1..$i);
+    $A[$i][1] = \@tempA1;
+    $csize = 2;
+    while ($csize+1<=$i) {            
+        my @temp0 = @{$A[$i-1][$csize]} ;
+        my @temp1 = map{ [ @{$_}, ] } @temp0;      # C(n-1,r)
+        my @temp2 = @{$A[$i-1][$csize-1]};         # C(n-1,r-1)
+        push @temp1, map { [ @{$_} , $i] } @temp2; # addition   
+        $A[$i][$csize] = \@temp1;
+        $csize++;
+    }
+    $A[$i][$i] =[[1..$i]];
+    $i++;
+}
+
+#$x = Data::Dumper->new(\@A);        # lines for testing
+#print $x->Dump;                     # lines for testing
+
+print "\$m = $m ; \$n = $n  \n";
+print "\n";
+
+
+my @temp = @{ $A[$m][$n] };
+foreach my $arr (@temp) {
+    print "[", join ",", @{$arr}; print "]";
+    print "\n";
+}
+
+print "\n";
-- 
cgit