Imported my solutions to challenge 103 (btw, submission date on main web page was wrong)

5 files changed, 305 insertions, 84 deletions

diff --git a/challenge-103/duncan-c-white/OptimizingTask1 b/challenge-103/duncan-c-white/OptimizingTask1
deleted file mode 100644
index f108fc1873..0000000000
--- a/challenge-103/duncan-c-white/OptimizingTask1
+++ /dev/null
@@ -1,50 +0,0 @@
-tried some optimizations of task 1 (rare numbers).  All times are for n==8 or 9
-I used Devel::NYTProf to profile each version, then made small optimizations,
-then reprofiled.  See "run.sh" for how to run a particular version through
-the profiler, generate the report, and copy it into a web-accessible directory
-for viewing:
-
-ch-1.pl:	the original, not optimized
-	time(8):	0:34.31
-	time(9):        5:56:10
-
-ch-1a.pl:	observation from rare numbers webpage ("Properties of.."
-		section): rare numbers start with even top digit
-	time(8):   0:24.46
-	time(9):   4:10.61
-
-ch-1b.pl:	only consider rare numbers starting with even top digit..
-	time(8):   0:15.35 
-	time(9):   2:44.34
-
-ch-1c.pl: 	lots of optimizations, especially 3 separate rare block
-		functions: rareblock(), rareblock05() and rareblock2378().
-	time(8):   0:06.35
-	time(9):   1:06.64
-
-ch-1d.pl: lots more optimizations, especially: rather than generate x and
-		test x%10 == d, generate y (1/10th the range) and make
-		x = 10y + d: 1/10th the work, but same x's as before
-	time(8):   0:03.92
-	time(9):   0:40.21
-
-ch-1e.pl: inlined israre() into the slowest rareblock2378() func
-	time(8):   0:03.39
-	time(9):   0:34.49
-
-ch-1f.pl: inlined israre() into the next slowest rareblock05() func
-	time(8):   0:03.12
-	time(9):   0:31.47
-
-ch-1g.pl: inlined israre() into the last rareblock() func
-	time(8):   0:02.94
-	time(9):   0:28.79
-
-ch-1h.pl: inlined perfectsquare() everywhere
-	time(8):   0:02.15
-	time(9):   0:21.20
-
-ch-1i.pl: reintroduced israre() but with two inlined calls to perfectsquare()
-	sweet spot: clear, shows problem structure nicely, plus pretty fast
-	time(8):   0:03.23
-	time(9):   0:32.34
diff --git a/challenge-103/duncan-c-white/README b/challenge-103/duncan-c-white/README
index 77c6612c7d..bd7e75deb8 100644
--- a/challenge-103/duncan-c-white/README
+++ b/challenge-103/duncan-c-white/README
@@ -1,54 +1,96 @@
-Task 1: "Rare Numbers
+Task 1: "Chinese Zodiac
 
-You are given a positive integer $N.
+You are given a year $year.
 
-Write a script to generate all Rare numbers of size $N if exists. Please
-read http://www.shyamsundergupta.com/rare.htm for more information about it.
+Write a script to determine the Chinese Zodiac for the given year
+$year. Please check out https://en.wikipedia.org/wiki/Chinese_zodiac
+for more information about it.
 
-Examples
+The animal cycle: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat,
+Monkey, Rooster, Dog, Pig.
 
-(a) 2 digits: 65
-(b) 6 digits: 621770
-(c) 9 digits: 281089082
+The element cycle: Wood, Fire, Earth, Metal, Water.
+
+Example 1:
+
+    Input: 2017
+    Output: Fire Rooster
+
+Example 2:
+
+    Input: 1938
+    Output: Earth Tiger
 "
 
-My notes: ok, interesting question.  In summary: R (a +ve no) is a Rare No
-iff R + reverse(R) and R - reverse(R) are both perfect squares.
-So: generate and test time.
+My notes: ok, so seems to be a 12 year cycle of animal names, intertwined
+with a 10 year cycle of 5 elements, two successive years having the same
+element each time.
 
-SEE ALSO OptimizingTask1 for an account of a series of profiling-driven
-optimizations that I made to speed up finding rare numbers.  Overall, my
-fastest version ran approx 18 times faster than the original.
 
+Task 2: "What's playing?
+Submitted by: Albert Croft
 
+Working from home, you decided that on occasion you wanted some background
+noise while working. You threw together a network streamer to continuously
+loop through the files and launched it in a tmux (or screen) session,
+giving it a directory tree of files to play. During the day, you connected
+an audio player to the stream, listening through the workday, closing
+it when done.
 
-Task 2: "Hash-counting String
+For weeks you connect to the stream daily, slowly noticing a gradual drift
+of the media. After several weeks, you take vacation. When you return,
+you are pleasantly surprised to find the streamer still running. Before
+connecting, however, if you consider the puzzle of determining which
+track is playing.
 
-You are given a positive integer $N.
+After looking at a few modules to read info regarding the media, a
+quick bit of coding gave you a file list. The file list is in a simple
+CSV format, each line containing two fields: the first the number of
+milliseconds in length, the latter the media's title (this example is
+of several episodes available from the MercuryTheatre.info):
 
-Write a script to produce Hash-counting string of that length.
+    1709363,"Les Miserables Episode 1: The Bishop (broadcast date: 1937-07-23)"
+    1723781,"Les Miserables Episode 2: Javert (broadcast date: 1937-07-30)"
+    1723781,"Les Miserables Episode 3: The Trial (broadcast date: 1937-08-06)"
+    1678356,"Les Miserables Episode 4: Cosette (broadcast date: 1937-08-13)"
+    1646043,"Les Miserables Episode 5: The Grave (broadcast date: 1937-08-20)"
+    1714640,"Les Miserables Episode 6: The Barricade (broadcast date: 1937-08-27)"
+    1714640,"Les Miserables Episode 7: Conclusion (broadcast date: 1937-09-03)"
 
-The definition of a hash-counting string is as follows:
+For this script, you can assume to be provided the following information:
 
-- the string consists only of digits 0-9 and hashes, '#'
+    * the value of $^T ($BASETIME) of the streamer script,
+    * the value of time(), and
+    * a CSV file containing the media to play consisting of the length
+      in milliseconds and an identifier for the media (title, filename,
+      or other).
 
-- there are no two consecutive hashes: '##' does not appear in your string
-- the last character is a hash
-- the number immediately preceding each hash (if it exists) is the position
-  of that hash in the string, with the position being counted up from 1
+Write a program to output which file is currently playing. For purposes
+of this script, you may assume gapless playback, and format the output
+as you see fit.
 
-It can be shown that for every positive integer N there is exactly one
-such length-N string.
+Optional: Also display the current position in the media as a time-like value.
 
-Examples:
+Example:
+UPDATED: Input parameters as reported by many members [2021-03-08 16:20 UK TIME].
 
-	(a) "#" is the counting string of length 1
-	(b) "2#" is the counting string of length 2
-	(c) "#3#" is the string of length 3
-	(d) "#3#5#7#10#" is the string of length 10
-	(e) "2#4#6#8#11#14#" is the string of length 14
-"
+Input: 3 command line parameters: start time, current time, file name
 
-My notes: ok, weird.  Can we directly generate the single
-hash-counting-string of length N?  I think we can..  Turns out to be easy.
+    # starttime
+    1606134123
+
+    # currenttime
+    1614591276
+
+    # filelist.csv
+
+Output:
+
+    "Les Miserables Episode 1: The Bishop (broadcast date: 1937-07-23)"
+    00:10:24
+"
 
+My notes: ok.  So basically compute currduration=1000*(currenttime-starttime)
+(in milliseconds) and then remove any number of complete song-cycles from
+that, and then work out which song should be playing.  Note that song
+lengths in the CSV file are in milliseconds, and every millisecond counts.
diff --git a/challenge-103/duncan-c-white/perl/ch-1.pl b/challenge-103/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..7211e21dfa
--- /dev/null
+++ b/challenge-103/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,67 @@
+#!/usr/bin/perl
+# 
+# Task 1: "Chinese Zodiac
+# 
+# You are given a year $year.
+# 
+# Write a script to determine the Chinese Zodiac for the given year
+# $year. Please check out https://en.wikipedia.org/wiki/Chinese_zodiac
+# for more information about it.
+# 
+# The animal cycle: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat,
+# Monkey, Rooster, Dog, Pig.
+# 
+# The element cycle: Wood, Fire, Earth, Metal, Water.
+# 
+# Example 1:
+# 
+#     Input: 2017
+#     Output: Fire Rooster
+# 
+# Example 2:
+# 
+#     Input: 1938
+#     Output: Earth Tiger
+# "
+# 
+# My notes: ok, so seems to be a 12 year cycle of animal names, intertwined
+# with a 10 year cycle of 5 elements, two successive years having the same
+# element each time.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Data::Dumper;
+
+my $debug=0;
+die "Usage: chinese-zodiac [--debug] YEAR\n"
+	unless GetOptions( "debug" => \$debug )
+	    && @ARGV==1;
+
+my $year = shift;
+
+my @animal = qw(Rat Ox Tiger Rabbit Dragon Snake Horse
+		Goat Monkey Rooster Dog Pig);
+my @element = qw(Wood Wood Fire Fire Earth Earth Metal Metal Water Water);
+
+my $y = 1924;
+my $e = 0;	# wood
+my $a = 0;  	# rat
+
+# the whole cycle lasts 60 years.. so find start of cycle before $year
+for( ; $year < $y; $y -= 60 )
+{
+}
+say "debug: year=$year, y=$y" if $debug;
+
+for( ; $year > $y; $y++ )
+{
+	$a++;
+	$a %= @animal;
+	$e++;
+	$e %= @element;
+}
+
+say "$element[$e] $animal[$a]";
diff --git a/challenge-103/duncan-c-white/perl/ch-2.pl b/challenge-103/duncan-c-white/perl/ch-2.pl
new file mode 100755
index 0000000000..b04b147dd3
--- /dev/null
+++ b/challenge-103/duncan-c-white/perl/ch-2.pl
@@ -0,0 +1,155 @@
+#!/usr/bin/perl
+# 
+# Task 2: "What's playing?
+# Submitted by: Albert Croft
+# 
+# Working from home, you decided that on occasion you wanted some background
+# noise while working. You threw together a network streamer to continuously
+# loop through the files and launched it in a tmux (or screen) session,
+# giving it a directory tree of files to play. During the day, you connected
+# an audio player to the stream, listening through the workday, closing
+# it when done.
+# 
+# For weeks you connect to the stream daily, slowly noticing a gradual drift
+# of the media. After several weeks, you take vacation. When you return,
+# you are pleasantly surprised to find the streamer still running. Before
+# connecting, however, if you consider the puzzle of determining which
+# track is playing.
+# 
+# After looking at a few modules to read info regarding the media, a
+# quick bit of coding gave you a file list. The file list is in a simple
+# CSV format, each line containing two fields: the first the number of
+# milliseconds in length, the latter the media's title (this example is
+# of several episodes available from the MercuryTheatre.info):
+# 
+#    1709363,"Les Miserables Episode 1: The Bishop (broadcast date: 1937-07-23)"
+#    1723781,"Les Miserables Episode 2: Javert (broadcast date: 1937-07-30)"
+#    1723781,"Les Miserables Episode 3: The Trial (broadcast date: 1937-08-06)"
+#    1678356,"Les Miserables Episode 4: Cosette (broadcast date: 1937-08-13)"
+#    1646043,"Les Miserables Episode 5: The Grave (broadcast date: 1937-08-20)"
+#    1714640,"Les Miserables Episode 6: The Barricade (broadcast date: 1937-08-27)"
+#    1714640,"Les Miserables Episode 7: Conclusion (broadcast date: 1937-09-03)"
+# 
+# For this script, you can assume to be provided the following information:
+# 
+#     * the value of $^T ($BASETIME) of the streamer script,
+#     * the value of time(), and
+#     * a CSV file containing the media to play consisting of the length
+#       in milliseconds and an identifier for the media (title, filename,
+#       or other).
+# 
+# Write a program to output which file is currently playing. For purposes
+# of this script, you may assume gapless playback, and format the output
+# as you see fit.
+# 
+# Optional: Also display the current position in the media as a time-like value.
+# 
+# Example:
+# UPDATED: Input parameters as reported by many members [2021-03-08 16:20 UK TIME].
+# 
+# Input: 3 command line parameters: start time, current time, file name
+# 
+#     # starttime
+#     1606134123
+# 
+#     # currenttime
+#     1614591276
+# 
+#     # filelist.csv
+# 
+# Output:
+# 
+#     "Les Miserables Episode 1: The Bishop (broadcast date: 1937-07-23)"
+#     00:10:24
+# "
+# 
+# My notes: ok.  So basically compute currduration=1000*(currenttime-starttime)
+# (in milliseconds) and then remove any number of complete song-cycles from
+# that, and then work out which song should be playing.  Note that song
+# lengths in the CSV file are in milliseconds, and every millisecond counts.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Function::Parameters;
+use Getopt::Long;
+use Data::Dumper;
+use Text::CSV qw(csv);
+use List::Util qw(sum);
+
+#
+# my $fmt = formatms($ms);
+#	Format milliseconds $ms as something
+#	nicer, eg 0h10m5s..  return the formatted string.
+#
+fun formatms( $ms )
+{
+	my $t = int($ms/1000);
+
+	my $s = $t % 60;
+	$t = int($t/60);
+	my $result = sprintf( "%02d", $s );
+
+	my $m = $t % 60;
+	$t = int($t/60);
+	$result = sprintf( "%02d:$result", $m );
+	#return $result if $t==0;
+
+	$result = sprintf( "%02d:$result", $t );
+	return $result;
+}
+
+
+
+my $debug=0;
+die "Usage: whats-playing [--debug] STARTTIME CURRTIME CSVFILENAME\n" unless
+	GetOptions( "debug" => \$debug ) &&
+	@ARGV==3;
+
+my( $starttime, $currtime, $csvfilename ) = @ARGV;
+
+die "whats-playing: starttime $starttime must be <= $currtime\n"
+	if $starttime > $currtime;
+
+my $t = 1000*($currtime-$starttime);
+
+say "debug: starttime=$starttime, currtime=$currtime, t=$t (".formatms($t).")"
+	if $debug;
+
+my $aop = csv( in => $csvfilename );
+
+# aop is an array of [ $duration, $title ] pairs
+# with all durations in milliseconds
+
+if( $debug )
+{
+	foreach my $pair (@$aop)
+	{
+		my $fmt = formatms($pair->[0]);
+		say "$fmt, $pair->[1]";
+	}
+}
+
+# find whole cycle length: sum of durations
+my $cycleduration = sum( map { $_->[0] } @$aop );
+
+say "cycleduration: $cycleduration (".formatms($cycleduration).")" if $debug;
+
+# bring $t into the current cycle
+$t %= $cycleduration;
+
+say "t: $t (".formatms($t).")" if $debug;
+
+# find which song $t is in..
+my $songno = 0;
+for(;;)
+{
+	my $d = $aop->[$songno]->[0];
+last if $t < $d;
+	$t -= $d;
+	$songno++;
+}
+
+say "$aop->[$songno]->[1]";
+say "time within song: ".formatms($t+1);
diff --git a/challenge-103/duncan-c-white/perl/filelist.csv b/challenge-103/duncan-c-white/perl/filelist.csv
new file mode 100644
index 0000000000..9428b93004
--- /dev/null
+++ b/challenge-103/duncan-c-white/perl/filelist.csv
@@ -0,0 +1,7 @@
+1709363,"Les Miserables Episode 1: The Bishop (broadcast date: 1937-07-23)"
+1723781,"Les Miserables Episode 2: Javert (broadcast date: 1937-07-30)"
+1723781,"Les Miserables Episode 3: The Trial (broadcast date: 1937-08-06)"
+1678356,"Les Miserables Episode 4: Cosette (broadcast date: 1937-08-13)"
+1646043,"Les Miserables Episode 5: The Grave (broadcast date: 1937-08-20)"
+1714640,"Les Miserables Episode 6: The Barricade (broadcast date: 1937-08-27)"
+1714640,"Les Miserables Episode 7: Conclusion (broadcast date: 1937-09-03)"