Merge pull request #5295 from dcw803/master

imported my solutions to this week's tasks…

3 files changed, 194 insertions, 27 deletions

diff --git a/challenge-140/duncan-c-white/README b/challenge-140/duncan-c-white/README
index d2eacb517a..90ddabae47 100644
--- a/challenge-140/duncan-c-white/README
+++ b/challenge-140/duncan-c-white/README
@@ -1,45 +1,67 @@
-TASK #1 - JortSort
+TASK #1 - Add Binary
 
-You are given a list of numbers.
+You are given two decimal-coded binary numbers, $a and $b.
 
-Write a script to implement JortSort. It should return true/false
-depending if the given list of numbers are already sorted.
+Write a script to simulate the addition of the given binary numbers.
 
-Example 1:
+Example 1
 
-	Input: @n = (1,2,3,4,5)
-	Output: 1
+	Input: $a = 11; $b = 1;
+	Output: 100
 
-	Since the array is sorted, it prints 1.
+Example 2
 
-Example 2:
+	Input: $a = 101; $b = 1;
+	Output: 110
 
-	Input: @n = (1,3,2,4,5)
-	Output: 0
+Example 3
 
-	Since the array is NOT sorted, it prints 0.
+	Input: $a = 100; $b = 11;
+	Output: 111
 
-MY NOTES: Very easy.  Don't know what "JortSort" means, but this is
-just the linear "IsSorted" function..
+MY NOTES: Very easy.  Extract least significant binary digit via $a % 10,
+implement full adder (bit,bit,carryin)->(bit,carryout), recurse and recombine.
 
 
-TASK #2 - Long Primes
+TASK #2 - Multiplication Table
 
-Write a script to generate first 5 Long Primes.
+You are given 3 positive integers, $i, $j and $k.
 
-A prime number (p) is called Long Prime if (1/p) has an infinite decimal expansion repeating every (p-1) digits.
+Write a script to print the $kth element in the sorted multiplication
+table of $i and $j.
 
-Example
+Example 1
 
-	7 is a long prime since 1/7 = 0.142857142857...
-	The repeating part (142857) size is 6 i.e. one less than the prime number 7.
+	Input: $i = 2; $j = 3; $k = 4
+	Output: 3
 
-	Also 17 is a long prime since 1/17 = 0.05882352941176470588235294117647...
-	The repeating part (0588235294117647) size is 16 i.e. one less than the prime number 17.
+Since the multiplication of 2 x 3 is as below:
 
-	Another example, 2 is not a long prime as 1/2 = 0.5.
-	There is no repeating part in this case.
+    1 2 3
+    2 4 6
 
-MY NOTES: Sounds pretty easy.  First generate some primes (have code to do that using Sieve of
-        Erathosthenes).  Then check each prime p to see if 1/p's 2*p long decimal fraction
-	contains the same sequence p-1 digits long.
+The sorted multiplication table:
+
+    1 2 2 3 4 6
+
+Now the 4th element in the table is "3".
+
+Example 2
+
+	Input: $i = 3; $j = 3; $k = 6
+	Output: 4
+
+Since the multiplication of 3 x 3 is as below:
+
+    1 2 3
+    2 4 6
+    3 6 9
+
+The sorted multiplication table:
+
+    1 2 2 3 3 4 6 6 9
+
+Now the 6th element in the table is "4".
+
+
+MY NOTES: Sounds pretty easy.  The table's ith row is (1..$j) * $i.
diff --git a/challenge-140/duncan-c-white/perl/ch-1.pl b/challenge-140/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..1c0525f47e
--- /dev/null
+++ b/challenge-140/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,73 @@
+#!/usr/bin/perl
+# 
+# TASK #1 - Add Binary
+# 
+# You are given two decimal-coded binary numbers, $a and $b.
+# 
+# Write a script to simulate the addition of the given binary numbers.
+# 
+# Example 1
+# 
+# 	Input: $a = 11; $b = 1;
+# 	Output: 100
+# 
+# Example 2
+# 
+# 	Input: $a = 101; $b = 1;
+# 	Output: 110
+# 
+# Example 3
+# 
+# 	Input: $a = 100; $b = 11;
+# 	Output: 111
+# 
+# MY NOTES: Very easy.  Extract least significant binary digit via $a % 10,
+# implement full adder (bit,bit,carryin)->(bit,carryout), recurse and recombine.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Function::Parameters;
+#use Data::Dumper;
+
+
+my $debug=0;
+die "Usage: dcb-add x y\n" unless
+	GetOptions( "debug"=>\$debug ) && @ARGV==2;
+my( $x, $y ) = @ARGV;
+
+die "dcb-add: $x not a decimal coded binary value\n"
+	if $x eq '' || $x =~ /[^01]/;
+
+die "dcb-add: $y not a decimal coded binary value\n"
+	if $y eq '' || $y =~ /[^01]/;
+
+#
+# my $result = dcb_add( $x, $y, $carry );
+#	Perform a binary addition of $x and $y, 2 decimal-encoded
+#	binary values (i.e. in which every digit is either 0 and 1),
+#	and the 0 or 1 $carry, and return the decimal-encoded result.
+#
+#	I could make this iterative if desired, using a sum-so-far, and
+#	a current-power-of-10 to multiply by.
+#
+fun dcb_add( $x, $y, $carry )
+{
+	my $lxd = $x % 10;
+	my $lyd = $y % 10;
+	my $sum = $lxd + $lyd + $carry;
+	$carry = int($sum/2);
+	$sum %= 2;
+	$x = int($x/10);
+	$y = int($y/10);
+	return $sum if $x == 0 && $y == 0 && $carry == 0;
+
+	my $result = dcb_add( $x, $y, $carry );
+	return 10 * $result + $sum;
+}
+
+
+my $result = dcb_add( $x, $y, 0 );
+say $result;
diff --git a/challenge-140/duncan-c-white/perl/ch-2.pl b/challenge-140/duncan-c-white/perl/ch-2.pl
new file mode 100755
index 0000000000..68663befcd
--- /dev/null
+++ b/challenge-140/duncan-c-white/perl/ch-2.pl
@@ -0,0 +1,72 @@
+#!/usr/bin/perl
+# 
+# TASK #2 - Multiplication Table
+# 
+# You are given 3 positive integers, $i, $j and $k.
+# 
+# Write a script to print the $kth element in the sorted multiplication
+# table of $i and $j.
+# 
+# Example 1
+# 
+# 	Input: $i = 2; $j = 3; $k = 4
+# 	Output: 3
+# 
+# Since the multiplication of 2 x 3 is as below:
+# 
+#     1 2 3
+#     2 4 6
+# 
+# The sorted multiplication table:
+# 
+#     1 2 2 3 4 6
+# 
+# Now the 4th element in the table is "3".
+# 
+# Example 2
+# 
+# 	Input: $i = 3; $j = 3; $k = 6
+# 	Output: 4
+# 
+# Since the multiplication of 3 x 3 is as below:
+# 
+#     1 2 3
+#     2 4 6
+#     3 6 9
+# 
+# The sorted multiplication table:
+# 
+#     1 2 2 3 3 4 6 6 9
+# 
+# Now the 6th element in the table is "4".
+# 
+# MY NOTES: Sounds pretty easy.  The table's ith row is (1..$j) * $i.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Function::Parameters;
+use Getopt::Long;
+use Data::Dumper;
+
+my $debug = 0;
+
+die "Usage: m-t [-d|--debug] I J K\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV==3;
+my( $i, $j, $k ) = @ARGV;
+
+my @table;
+
+foreach my $row (1..$i)
+{
+	foreach my $col (1..$j)
+	{
+		push @table, $col*$row;
+	}
+}
+#die Dumper \@table;
+
+@table = sort @table;
+
+say $table[$k-1];