Merge pull request #1285 from saiftynet/branch-048

Challenge-048 solutions by saiftynet submitted using EZPWC

2 files changed, 125 insertions, 0 deletions

diff --git a/challenge-048/saiftynet/perl/ch-1.pl b/challenge-048/saiftynet/perl/ch-1.pl
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+++ b/challenge-048/saiftynet/perl/ch-1.pl
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+#!/usr/env/perl
+# Task 1 Challenge 048 Solution by saiftynet
+# 
+# Survivor
+# 
+# There are 50 people standing in a circle in position 1 to 50. The person 
+# standing at position 1 has a sword. He kills the next person i.e. standing 
+# at position 2 and pass on the sword to the immediate next i.e. person standing 
+# at position 3. Now the person at position 3 does the same and it goes on 
+# until only one survives.
+# 
+# Write a script to find out the survivor.
+# 
+# Probably the best way to implement a circular list is to shift an element
+# and then push it back on the ther end...s the whole array rotates, and
+# our index remain in the same position, rather than to have a pointer
+# that is checked to see if it has reached the boundary every time and 
+# reset to end or start depending on which way we moving the pointer.
+#
+# For the purposes of this task, we will have the sword holder at position 0
+# the victime is at postion 1, and the sword receiver is at position 2.
+#
+# For a bit of fun, an attempt is made at animating this.  This works on
+# an 80x24 console that supports `cls` in Windows or `clear` in Linux
+# or OSX
+
+
+my @circleList=(1..50);
+
+# clear screen can be done using Term::XXX, but in case the module is
+# not accessible, I have adapted an answer from
+# https://stackoverflow.com/questions/197933
+
+my $clearScreen=( $^O=~/Win/)?`cls`:`clear`;
+
+my $animate=1;       # set this to 0 if you dont want to animate.
+ 
+while (scalar @circleList >1){
+  if ($animate){     # animation is optional; may not work or be desired
+	 select(undef, undef, undef, 0.25); 
+	 print $clearScreen;
+     circle(\@circleList);
+  }
+  else{
+	   print join ",",@circleList;
+  }
+  my $killer=shift @circleList;    # get the killer, ready to push to end
+  my $killed=shift @circleList;    # get the killed and dump it
+  push @circleList,$killer;        # push killer to end of list
+  print "\n$killer killed $killed".# display results
+        ( (scalar @circleList > 1)?
+           " and passed sword to $circleList[0]\n":
+           " and is last man standing!!\n");
+  
+}
+
+# subroutine to plot a circular list in a circle. 
+sub circle{  
+	my $circleList=shift;         
+	my @plotArea   = ();          # reset plot area
+    push @plotArea, [("  ") x 40,"\n"]
+         foreach (0..16);         # two spaces per point
+     
+    my $center=[9,20];            # adjust for different console sizes
+    my $radius=[8,18];            # adjust for different console sizes
+     foreach my $angle (0..@$circleList-1){
+       $plotArea [$$center[0]+$$radius[0]*sin($angle*6.28/@$circleList)]
+                 [$$center[1]-$$radius[1]*cos($angle*6.28/@$circleList)]
+                 =$$circleList[$angle];       
+     }
+         print @{$_} foreach (@plotArea); # the plot area
+}
diff --git a/challenge-048/saiftynet/perl/ch-2.pl b/challenge-048/saiftynet/perl/ch-2.pl
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+#!/usr/env/perl
+# Task 2 Challenge 048 Solution by saiftynet
+# 
+# Palindrome Dates
+# 
+# Write a script to print all Palindrome Dates between 2000 and 2999. The 
+# format of date is mmddyyyy. For example, the first one was on October 2, 
+# 2001 as it is represented as 10022001.
+
+# With Palindromic dates, the year contains the digits of the month
+# and date, so can be easiy derived from the year using substr.
+# The MMDDYYY format is a requirement of the task, but is probably the
+# most illogical date format (and therefore naturally favoured by
+# Americans).
+# DDMMYYY (the most common worldwide) and YYYYMMDD (ISO 8601, the most
+# logical and least ambiguous format) also can produce different
+# palindromic dates. This script can yield these formats too.
+
+# There are many better ways of getting valid dates via modules.
+# Much more interesting to roll-your-own, so didn't use them.
+
+
+# Changing this string will show palindromes in other formats
+# valid formats are MDY, DMY and YMD.  The format can also be
+# passed from the command line using e.g. perl ch-2.pl DMY
+
+my $format = $ARGV[0] // "MDY";  # valid strings "MDY", "DMY" and "YMD".
+die 'Invalid string, must be "MDY", "DMY" or "YMD"' if $format !~/^MDY|DMY|YMD\b/;
+
+foreach my $yyyy (2000..2999){
+   my $mm   =  substr($yyyy,3,1).substr($yyyy,2,1);
+   my $dd   =  substr($yyyy,1,1).substr($yyyy,0,1);
+   
+   ($mm,$dd)=($dd,$mm) if $format eq "DMY";    # Swap if DDMMYYY required
+   
+   next if ($mm >12 or $mm ==0);               # Discard invalid months
+   if ($mm =~/02/){                            # February is special case
+       $notLeapYear=($y % 4)||(!($y%100)&&($y%400));
+       my $FebDays=(28+($notLeapYear?0:1))."";
+       next if ($dd gt $FebDays or $dd eq "00")
+   }
+   elsif ($mm=~/^01|03|05|07|08|10|12/){       # months with 31 days
+       next if ($dd gt "31"     or $dd eq "00");
+   } 
+   else{                                       # all the rest have 30 days
+       next if ($dd gt "30"     or $dd eq "00");
+   
+  }
+  
+   print "M $mm, D $dd, Y $yyyy :  $mm$dd$yyyy \n" if $format eq "MDY";
+   print "D $dd, M $mm, Y $yyyy :  $dd$mm$yyyy \n" if $format eq "DMY";
+   print "Y $yyyy, M $mm, D $dd :  $yyyy$mm$dd \n" if $format eq "YMD";   
+}