Merge pull request #5092 from dcw803/master

imported my solutions to this week's tasks..

3 files changed, 184 insertions, 34 deletions

diff --git a/challenge-135/duncan-c-white/README b/challenge-135/duncan-c-white/README
index 83854546f8..9e73de07f7 100644
--- a/challenge-135/duncan-c-white/README
+++ b/challenge-135/duncan-c-white/README
@@ -1,52 +1,56 @@
-TASK #1 - Pandigital Numbers
+TASK #1 - Middle 3-digits
 
-Write a script to generate first 5 Pandigital Numbers in base 10.
+You are given an integer.
 
-As per the wikipedia, it says:
+Write a script find out the middle 3-digits of the given integer, if
+possible otherwise throw sensible error.
 
-A pandigital number is an integer that in a given base has among its
-significant digits each digit used in the base at least once.
-The smallest base 10 pandigital number is 1023456789, and subsequent
-ones are lexicographic permutations, ie. 1023456798, 1023456879...
+Example 1
 
-MY NOTES: Basically just needs a standard lexicographic permutation algorithm,
-with the initial value to permute being 1023456789.
+  Input: $n = 1234567
+  Output: 345
 
-TASK #2 - Distinct Terms Count
+Example 2
 
-You are given 2 positive numbers, $m and $n.
+  Input: $n = -123
+  Output: 123
 
-Write a script to generate multiplication table and display count of distinct terms.
+Example 3
 
-Example 1
+  Input: $n = 1
+  Output: too short
+
+Example 4
+
+  Input: $n = 10
+  Output: even number of digits
+
+MY NOTES: Pretty easy, although it's not clear how to always treat negative numbers.
+Assume abs() them.
 
-Input: $m = 3, $n = 3
-Output:
 
-      x | 1 2 3
-      --+------
-      1 | 1 2 3
-      2 | 2 4 6
-      3 | 3 6 9
+TASK #2 - Validate SEDOL
+
+You are given 7-characters alphanumeric SEDOL.
+
+Write a script to validate the given SEDOL. Print 1 if it is a valid SEDOL otherwise 0.
+
+For more information about SEDOL, please checkout https://en.wikipedia.org/wiki/SEDOL
+
+Example 1
 
-Distinct Terms: 1, 2, 3, 4, 6, 9
-Count: 6
+  Input: $SEDOL = '2936921'
+  Output: 1
 
 Example 2
 
-Input: $m = 3, $n = 5
-Output:
+  Input: $SEDOL = '1234567'
+  Output: 0
 
-      x | 1  2  3  4  5
-      --+--------------
-      1 | 1  2  3  4  5
-      2 | 2  4  6  8 10
-      3 | 3  6  9 12 15
+Example 3
 
-Distinct Terms: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15
-Count: 11
+  Input: $SEDOL = 'B0YBKL9'
+  Output: 1
 
+MY NOTES: Pretty easy
 
-MY NOTES: Pretty easy, the distinct terms just need a set (hash) as usual.
-The tricky bit is the pretty layout of the multiplication table, especially
-getting the correct column widths..
diff --git a/challenge-135/duncan-c-white/perl/ch-1.pl b/challenge-135/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..44c5630e13
--- /dev/null
+++ b/challenge-135/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,54 @@
+#!/usr/bin/perl
+# 
+# TASK #1 - Middle 3-digits
+# 
+# You are given an integer.
+# 
+# Write a script find out the middle 3-digits of the given integer, if
+# possible otherwise throw sensible error.
+# 
+# Example 1
+# 
+#   Input: $n = 1234567
+#   Output: 345
+# 
+# Example 2
+# 
+#   Input: $n = -123
+#   Output: 123
+# 
+# Example 3
+# 
+#   Input: $n = 1
+#   Output: too short
+# 
+# Example 4
+# 
+#   Input: $n = 10
+#   Output: even number of digits
+# 
+# MY NOTES: Pretty easy, although it's not clear how to always treat negative numbers.
+# Assume abs() them.
+#
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+#use Data::Dumper;
+
+
+my $debug=0;
+die "Usage: middle-3-digits N\n" unless
+	GetOptions( "debug"=>\$debug ) && @ARGV==1;
+my $n = shift @ARGV;
+$n = abs($n);
+
+my $l = length($n);
+die "$n too short\n" if $l<3;
+
+die "even number of digits\n" if ($l&1)==0;
+
+my $midpos = int($l/2);
+
+say substr($n,$midpos-1,3);
diff --git a/challenge-135/duncan-c-white/perl/ch-2.pl b/challenge-135/duncan-c-white/perl/ch-2.pl
new file mode 100755
index 0000000000..8d911c173a
--- /dev/null
+++ b/challenge-135/duncan-c-white/perl/ch-2.pl
@@ -0,0 +1,92 @@
+#!/usr/bin/perl
+# 
+# TASK #2 - Validate SEDOL
+# 
+# You are given 7-characters alphanumeric SEDOL.
+# 
+# Write a script to validate the given SEDOL. Print 1 if it is a valid SEDOL otherwise 0.
+# 
+# For more information about SEDOL, please checkout https://en.wikipedia.org/wiki/SEDOL
+# 
+# Example 1
+# 
+#   Input: $SEDOL = '2936921'
+#   Output: 1
+# 
+# Example 2
+# 
+#   Input: $SEDOL = '1234567'
+#   Output: 0
+# 
+# Example 3
+# 
+#   Input: $SEDOL = 'B0YBKL9'
+#   Output: 1
+# 
+# MY NOTES: Pretty easy translation of the Javascript version in the SEDOL web page.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Function::Parameters;
+use Getopt::Long;
+use Data::Dumper;
+
+my $debug = 0;
+
+die "Usage: validate-sedol [-d|--debug] CODE\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV==1;
+my $code = shift @ARGV;
+my $l = length($code);
+
+die "$code length $l, not 7\n" unless $l == 7;
+
+ 
+my @weight = (1, 3, 1, 7, 3, 9, 1);
+
+
+#
+# my( $checkdigit, $errormessage ) = sedol_check_digit( $code );
+#	Take a 6-char SEDOL code, and calculate and return the
+#	7th digit (the check digit), or (undef, $errormessage) to
+#	indicate an error.
+#
+fun sedol_check_digit( $code )
+{
+
+    unless( $code =~ /^[0-9BCDFGHJ-NP-TV-Z]{6}$/ )
+    {
+	 return (undef, "Invalid SEDOL number '$code'");
+    }
+    my $sum = 0;
+    my $l = length($code);
+    $code = lc($code);
+    for( my $i = 0; $i < $l; $i++)
+    {
+        my $char = substr($code,$i,1);
+	my $base36 = ($char =~ /^\d/) ? ord($char)-ord('0') : ord($char)+10-ord('a');
+	say "debug: code=$code, char=$char, base36=$base36, i=$i, w[i]==$weight[$i]" if $debug;
+	$sum += $weight[$i] * $base36;
+    }
+    my $check = (10 - $sum%10) % 10;
+    return ($check, undef);
+}
+
+
+#
+# my $validsedol = checkSedol( $text );
+#	Return 1 iff $text is a valid Sedol code; 0 otherwise.
+#
+fun checkSedol( $text )
+{
+	my $input = substr($text,0,6);
+	my( $checkdigit, $error ) = sedol_check_digit($input);
+	return 0 if defined $error;
+	say "debug: checkSedol($text): checkdigit = $checkdigit" if $debug;
+	return $text eq $input . $checkdigit;
+}
+
+
+my $validsedol = checkSedol( $code );
+say $validsedol ? 1 : 0;