Merge pull request #7507 from robbie-hatley/202

Robbie Hatley's Perl Solutions To The Weekly Challenge #202

4 files changed, 166 insertions, 0 deletions

diff --git a/challenge-202/robbie-hatley/README b/challenge-202/robbie-hatley/README
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--- a/challenge-202/robbie-hatley/README
+++ b/challenge-202/robbie-hatley/README
diff --git a/challenge-202/robbie-hatley/blog.txt b/challenge-202/robbie-hatley/blog.txt
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+https://hatley-software.blogspot.com/2023/01/robbie-hatleys-perl-solutions-to-weekly_31.html
\ No newline at end of file
diff --git a/challenge-202/robbie-hatley/perl/ch-1.pl b/challenge-202/robbie-hatley/perl/ch-1.pl
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+#! /usr/bin/perl
+
+# Robbie Hatley's Perl Solutions to The Weekly Challenge #202-1
+
+# DESCRIPTION OF PROBLEM:
+
+=pod
+
+Task 1: Consecutive Odds
+Submitted by: Mohammad S Anwar
+
+You are given an array of integers. Write a script to print 1 if there 
+are THREE consecutive odds in the given array otherwise print 0.
+
+Example 1:  Input: (1,5,3,6)  Output: 1
+Example 2:  Input: (2,6,3,5)  Output: 0
+Example 3:  Input: (1,2,3,4)  Output: 0
+Example 4:  Input: (2,3,5,7)  Output: 1
+
+=cut
+
+# IO NOTES:
+# NOTE: Default input is via built-in array of arrays.
+#       Non-default input can be provided through @ARGV.
+#       If using @ARGV, arguments should be a space-separated sequence
+#       of integers, which will be construed as being a single array.
+#
+# NOTE: Output is to stdout and will be 1 if 3 consecutive odds, else 0.
+
+# PRELIMINARIES:
+use v5.36;
+$,=' ';
+
+# SUBROUTINES: 
+sub tco (@a){
+   for (my $i = 0 ; $i <= $#a-2 ; ++$i){
+      if ( !($a[$i+0]%2) ) {$i += 0; next;}
+      if ( !($a[$i+1]%2) ) {$i += 1; next;}
+      if ( !($a[$i+2]%2) ) {$i += 2; next;}
+      return 1;}
+   return 0;}
+
+# DEFAULT INPUT:
+my @arrays = ([1,5,3,6],[2,6,3,5],[1,2,3,4],[2,3,5,7]);
+
+# NON-DEFAULT INPUT:
+if (@ARGV) {@arrays = ([@ARGV]);}
+
+# SCRIPT BODY:
+for (@arrays){
+   my @array = @{$_};
+   my $tco = tco(@array);
+   say '';
+   say "array = (@array)";
+   say "tco = $tco";}
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diff --git a/challenge-202/robbie-hatley/perl/ch-2.pl b/challenge-202/robbie-hatley/perl/ch-2.pl
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+#! /usr/bin/perl
+
+# Robbie Hatley's Perl Solutions to The Weekly Challenge #202-2
+
+# DESCRIPTION OF PROBLEM:
+
+=pod
+
+Task 2: Widest Valley
+Submitted by: E. Choroba
+
+Given a profile as a list of altitudes, return the leftmost widest valley.
+A valley is defined as a subarray of the profile consisting of two parts:
+the first part is non-increasing and the second part is non-decreasing.
+Either part can be empty.
+
+Example 1:  Input: 1, 5, 5, 2, 8               Output: 5, 5, 2, 8
+Example 2:  Input: 2, 6, 8, 5                  Output: 2, 6, 8
+Example 3:  Input: 9, 8, 13, 13, 2, 2, 15, 17  Output: 13, 13, 2, 2, 15, 17
+Example 4:  Input: 2, 1, 2, 1, 3               Output: 2, 1, 2
+Example 5:  Input: 1, 3, 3, 2, 1, 2, 3, 3, 2   Output: 3, 3, 2, 1, 2, 3, 3
+
+=cut
+
+# IO NOTES:
+#
+# NOTE: Input is via either built-in array of arrays, or @ARGV.
+#       If using @ARGV, arguments should be a space-separated sequence of
+#       integers, which will be interpreted as being a single array
+#
+# NOTE: Output will be to stdout and will be the contents of each array
+#       followed by the left-most widest valley within that array.
+
+# PRELIMINARIES:
+use v5.36;
+$"=", ";
+
+# DEFAULT INPUT:
+my @arrays =
+(
+   [1, 5, 5, 2, 8], 
+   [2, 6, 8, 5], 
+   [9, 8, 13, 13, 2, 2, 15, 17], 
+   [2, 1, 2, 1, 3], 
+   [1, 3, 3, 2, 1, 2, 3, 3, 2]
+);
+
+# NON-DEFAULT INPUT:
+if (@ARGV){@arrays=([@ARGV])}
+
+# SCRIPT BODY:
+for (@arrays){
+   my @array   = @{$_};  # Current array.
+   my $state   = 'L';    # State of valley wall: 'L'=Left, 'R'=Right.
+   my $width   = 0;      # Width of most-recent valley.
+   my $widbi   = 0;      # Beginning index of widest valley found so far.
+   my $widest  = 0;      # Width of widest valley found so-far.
+   my @valley  = ();     # Left-most widest valley found so far.
+   my $idx     = 0;      # Elevation index.
+   my $begin   = 0;      # Beginning index of current valley.
+   
+   # For each elevation change, decide what to do, based valley-wall state
+   # and on whether we've reached the last elevation yet:
+   for ( $idx = 1 ; $idx <= $#array ; ++$idx ){
+
+      # If we're on the Left Wall of our current valley, check to see if we
+      # just transitioned to the Right Wall:
+      if ($state eq 'L' && $array[$idx] > $array[$idx-1]){
+         $state = 'R';}
+
+      # If we're on the Right Wall of our current valley, check to see if we
+      # just transitioned to a new Left Wall:
+      if ($state eq 'R' && $array[$idx] < $array[$idx-1]){
+         # How wide was that valley we just left?
+         $width = $idx - $begin;
+
+         # Was that wider than the widest valley we've seen so far?
+         # If so, update widest-valley information accordingly:
+         if ($width > $widest){
+            $widbi  = $begin;
+            $widest = $width;}
+
+         # Our old valley ended, so now let's begin a new valley:
+         $begin = $idx;
+
+         # But also include any flat or down-sloping ground to the left
+         # of $idx as also being part of our new valley:
+         while ($begin >= 0 && $array[$begin-1]>=$array[$begin]){--$begin}
+
+         # We're now on the left wall of our new valley:
+         $state = 'L';}
+
+      # If end-of-array cuts off valley, then don't wait for current valley to
+      # terminate by R->L transition, because that can't happen! Instead,
+      # calculate size of current valley now, and update "widest valley"
+      # information if appropriate:
+      if ($idx == $#array){
+         $width = $idx + 1 - $begin;
+         if ($width > $widest){
+            $widbi  = $begin;
+            $widest = $width;}}}
+
+   # Set @valley to a slice of @array beginning with "widest beginning index"
+   # "$widbi" and having width "$widest":
+   @valley = @array[$widbi..$widbi+$widest-1];
+
+   # Print results:
+   say '';
+   say "Array of elevations     = (@array)";
+   say "Left-most widest valley = (@valley)"}