From fbfe92ee23c1aff2724ed81a681d35e7698aea51 Mon Sep 17 00:00:00 2001
From: Thomas Köhler <jean-luc@picard.franken.de>
Date: Mon, 5 Aug 2024 22:27:48 +0200
Subject: Add solution 281
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Thomas Köhler <jean-luc@picard.franken.de>
---
 challenge-281/jeanluc2020/blog-1.txt   |   1 +
 challenge-281/jeanluc2020/blog-2.txt   |   1 +
 challenge-281/jeanluc2020/perl/ch-1.pl |  68 ++++++++++++++++++++++
 challenge-281/jeanluc2020/perl/ch-2.pl | 103 +++++++++++++++++++++++++++++++++
 4 files changed, 173 insertions(+)
 create mode 100644 challenge-281/jeanluc2020/blog-1.txt
 create mode 100644 challenge-281/jeanluc2020/blog-2.txt
 create mode 100755 challenge-281/jeanluc2020/perl/ch-1.pl
 create mode 100755 challenge-281/jeanluc2020/perl/ch-2.pl

diff --git a/challenge-281/jeanluc2020/blog-1.txt b/challenge-281/jeanluc2020/blog-1.txt
new file mode 100644
index 0000000000..1d71d498ef
--- /dev/null
+++ b/challenge-281/jeanluc2020/blog-1.txt
@@ -0,0 +1 @@
+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-281-1.html
diff --git a/challenge-281/jeanluc2020/blog-2.txt b/challenge-281/jeanluc2020/blog-2.txt
new file mode 100644
index 0000000000..8b72113c8a
--- /dev/null
+++ b/challenge-281/jeanluc2020/blog-2.txt
@@ -0,0 +1 @@
+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-281-2.html
diff --git a/challenge-281/jeanluc2020/perl/ch-1.pl b/challenge-281/jeanluc2020/perl/ch-1.pl
new file mode 100755
index 0000000000..19cee92c1f
--- /dev/null
+++ b/challenge-281/jeanluc2020/perl/ch-1.pl
@@ -0,0 +1,68 @@
+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-281/#TASK1
+#
+# You are given coordinates, a string that represents the coordinates of a
+# square of the chessboard as shown below:
+#
+# 8 # # # #
+# 7# # # # 
+# 6 # # # #
+# 5# # # # 
+# 4 # # # #
+# 3# # # # 
+# 2 # # # #
+# 1# # # # 
+#  abcdefgh
+#
+# Write a script to return true if the square is light, and false if the square
+# is dark.
+#
+## Example 1
+##
+## Input: $coordinates = "d3"
+## Output: true
+#
+## Example 2
+##
+## Input: $coordinates = "g5"
+## Output: false
+#
+## Example 3
+##
+## Input: $coordinates = "e6"
+## Output: true
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# Let's map a through h to 1 through 8. That way, each square has coordinates
+# char/digit which map to digit/digit. We can observe that the sum of those
+# digits is even when the square is dark (this works because at the end of a
+# line, for example h1, we can jump to the beginning of the next line, and the
+# mapping jumps from 8:1 to 1:2 which changes evenness in both digits, keeping
+# it overall, and indeed we keep the light/dark by jumping there as well).
+# So if the sum of the mapped digits is even, we have a dark square. That's easy
+# to calculate.
+
+use strict;
+use warnings;
+
+check_color("d3");
+check_color("g5");
+check_color("e6");
+
+sub check_color {
+   my $coordinates = shift;
+   my $map = { "a" => 1, "b" => 2, "c" => 3, "d" => 4,
+      "e" => 5, "f" => 6, "g" => 7, "h" => 8 };
+   my ($char, $digit) = split //, $coordinates;
+   print "Input: $coordinates\n";
+   my $odd = ($map->{$char} + $digit) % 2;
+   if($odd) {
+      return print "Output: true\n";
+   }
+   return print "Output: false\n";
+}
diff --git a/challenge-281/jeanluc2020/perl/ch-2.pl b/challenge-281/jeanluc2020/perl/ch-2.pl
new file mode 100755
index 0000000000..9f10bebbe9
--- /dev/null
+++ b/challenge-281/jeanluc2020/perl/ch-2.pl
@@ -0,0 +1,103 @@
+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-281/#TASK2
+#
+# A Knight in chess can move from its current position to any square two rows
+# or columns plus one column or row away. So in the diagram below, if it starts
+# a S, it can move to any of the squares marked E.
+#
+# Write a script which takes a starting position and an ending position and
+# calculates the least number of moves required.
+#
+# https://theweeklychallenge.org/images/blog/week_281_task_2.png
+#
+## Example 1
+##
+## Input: $start = 'g2', $end = 'a8'
+## Ouput: 4
+##
+## g2 -> e3 -> d5 -> c7 -> a8
+#
+## Example 2
+##
+## Input: $start = 'g2', $end = 'h2'
+## Ouput: 3
+##
+## g2 -> e3 -> f1 -> h2
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# Some observations:
+# 1. The shortest path from one square to the directly neighboring
+#    square has length 5
+#    Example: a8->c7->e6->d8->c6->b8 (for all other combinations
+#    it's just shifted around, mirrored, or rotated by 90°)
+# 2. The shortest path from one square to its diagonal neighboar has
+#    length 2, except if it's in the corner (a8->b7 is one move to
+#    b6 or c7, then it's a case of walking to the directly neighboring
+#    square, so the length is 1+5=6 in this case)
+# 3. The shortest path to cover most of the distance on the board from
+#    one end to the next (or the opposing corner) is basically 4, plus
+#    some more steps to jump to the exact square you want to end up in
+# From this, we can assume there is an upper limit of how many steps are
+# required to go from any square to any other square: 4+6=10 steps
+# should be enough in any case.
+# So we can brute-force this with a max-depth of 10.
+
+use strict;
+use warnings;
+use List::Util qw(min any);
+
+knights_move("g2", "a8");
+knights_move("g2", "h2");
+
+sub knights_move {
+   my ($start, $end) = @_;
+   print "Input: $start -> $end\n";
+   my $l = min_length($start, $end, 1, []);
+   print "Output: $l\n";
+}
+
+sub min_length {
+   my ($start, $end, $step, $seen) = @_;
+   # print "=> [" . join(",", @$seen) . "] $start, $end, $step\n";
+   if($start eq $end) {
+      return 0;
+   }
+   if($step > 10 || any { $_ eq $start} @$seen) {
+      return 1000;
+   }
+   my $map = { "a" => 1, "b" => 2, "c" => 3, "d" => 4,
+      "e" => 5, "f" => 6, "g" => 7, "h" => 8 };
+   my $reverse_map = { 1 => "a", 2 => "b", 3 => "c", 4 => "d",
+      5 => "e", 6 => "f", 7 => "g", 8 => "h" };
+   my ($char1, $digit1) = split //, $start;
+   my ($char2, $digit2) = split //, $end;
+   my @lengths = ();
+   foreach my $direction ( ([-2, 1], [-2,-1], [-1,-2], [-1,2],
+      [2,1], [2,-1], [1,2], [1,-2]) ) {
+        my $c = $map->{$char1} + $direction->[0];
+        my $d = $digit1 + $direction->[1];
+        if(legal( $c, $d)) {
+           next if any  { $_ eq $start} @$seen;
+           my $l = 1 + min_length($reverse_map->{$c} . $d, $end, $step+1, [@$seen, $start] );
+           next unless $l;
+           push @lengths, $l if $l < 1000;
+        }
+   }
+   return min(@lengths, 1000);
+}
+
+sub legal {
+   my ($mapped_digit, $digit) = @_;
+   if($mapped_digit < 1 || $digit < 1) {
+      return 0;
+   }
+   if($mapped_digit > 8 || $digit > 8) {
+      return 0;
+   }
+   return 1;
+}
-- 
cgit 


From 5a74f63a80819bcaa7048779dadd508e09b114e5 Mon Sep 17 00:00:00 2001
From: Luis Mochan <mochan@fis.unam.mx>
Date: Mon, 5 Aug 2024 15:05:27 -0600
Subject: Solve PWC281

---
 challenge-281/wlmb/blog.txt     |  1 +
 challenge-281/wlmb/perl/ch-1.pl | 19 +++++++++++++++++++
 challenge-281/wlmb/perl/ch-2.pl | 42 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 challenge-281/wlmb/blog.txt
 create mode 100755 challenge-281/wlmb/perl/ch-1.pl
 create mode 100755 challenge-281/wlmb/perl/ch-2.pl

diff --git a/challenge-281/wlmb/blog.txt b/challenge-281/wlmb/blog.txt
new file mode 100644
index 0000000000..f505524efa
--- /dev/null
+++ b/challenge-281/wlmb/blog.txt
@@ -0,0 +1 @@
+https://wlmb.github.io/2024/08/04/PWC281/
diff --git a/challenge-281/wlmb/perl/ch-1.pl b/challenge-281/wlmb/perl/ch-1.pl
new file mode 100755
index 0000000000..94438ac772
--- /dev/null
+++ b/challenge-281/wlmb/perl/ch-1.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 281
+# Task 1:  Check Color
+#
+# See https://wlmb.github.io/2024/08/04/PWC281/#task-1-check-color
+use v5.36;
+die <<~"FIN" unless @ARGV;
+    Usage $0 P1 P2...
+    to test whether position Pi in a chessboard corresponds to a white square,
+    where Pi is of the form xy with x a letter in the range a-h and y a digit
+    in the range 1-8.
+    FIN
+for(@ARGV){
+    warn("Bad format: $_"), next unless /^([a-hA-H])([1-7])$/;
+    my $x=ord(lc $1)-ord("a"); # convert to number 0-7
+    my $y=$2-1;
+    my $result=($x+$y)%2?"True":"False";
+    say "$_ -> $result";
+}
diff --git a/challenge-281/wlmb/perl/ch-2.pl b/challenge-281/wlmb/perl/ch-2.pl
new file mode 100755
index 0000000000..9911a6cb36
--- /dev/null
+++ b/challenge-281/wlmb/perl/ch-2.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 281
+# Task 2:  Knight’s Move
+#
+# See https://wlmb.github.io/2024/08/04/PWC281/#task-2-knight’s-move
+use v5.36;
+use PDL;
+use PDL::NiceSlice;
+use experimental qw(for_list);
+die <<~"FIN" unless @ARGV && @ARGV%2==0;
+    Usage: $0 S1 E1...
+    to find how many moves are required for a knight to go from position Si
+    to position Ei in a chessboard.
+    The positions are given in the format xy where x is a letter in the
+    range a-h and denotes the horizontal position while y is a digit between 1 and 8
+    and denotes vertical position.
+    FIN
+my $moves=pdl[[1,2],[2,1]]; # Construct all moves of knight
+my $signs=pdl[1,-1];
+my $allmoves=pdl($moves, $moves*$signs, -$moves*$signs,-$moves)->clump(1,2);
+for my($start, $end)(@ARGV){
+    my ($current, $goal)=map{ # convert to coordinate vectors, origin at (0,0)
+	warn("Bad format: $_"), next unless /^([a-hA-H])([1-8])$/;
+	pdl(ord(lc $1)-ord("a"), $2-1)
+    } ($start, $end);
+    my $iteration=0;
+    my $visited=zeroes(8,8);
+    $visited->indexND($current).=1;
+    until(($current==$goal)->andover->any){ # until we reach the goal
+	my $next=($current+$allmoves->dummy(1))->clump(1,2); # jump to new positions
+	$current=$next
+	    ->dice_axis(  # remove invalid positions
+		 1, which(($next((0))>=0)&($next((0))<8)&($next((1))>=0)&($next((1))<8)))
+	    ->uniqvec;     # remove duplicates
+	$current=$current->dice_axis( # remove previously visited
+		     1, which(!$visited->indexND($current))
+	    );
+	$visited->indexND($current).=1;
+	++$iteration;
+    }
+    say "From $start to $end -> $iteration movements";
+}
-- 
cgit 


From 93a8115c85650e76505f7cb610b3a31cc61388c1 Mon Sep 17 00:00:00 2001
From: Conor Hoekstra <codereport@outlook.com>
Date: Mon, 5 Aug 2024 17:06:25 -0400
Subject: :sparkles: Week 281 in BQN

---
 challenge-281/conor-hoekstra/ch-1.bqn | 10 ++++++++++
 challenge-281/conor-hoekstra/ch-2.bqn | 16 ++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 challenge-281/conor-hoekstra/ch-1.bqn
 create mode 100644 challenge-281/conor-hoekstra/ch-2.bqn

diff --git a/challenge-281/conor-hoekstra/ch-1.bqn b/challenge-281/conor-hoekstra/ch-1.bqn
new file mode 100644
index 0000000000..3b0feeb2b6
--- /dev/null
+++ b/challenge-281/conor-hoekstra/ch-1.bqn
@@ -0,0 +1,10 @@
+# For up to date code:
+# https://github.com/codereport/bqn-code/blob/main/pwc/281-1.bqn
+
+IsDark ← 2|·+´48|-⟜'0'¨
+
+# Tests
+•Show IsDark "d3" # 1
+•Show IsDark "g5" # 0
+•Show IsDark "e6" # 1
+•Show IsDark "a1" # 0
diff --git a/challenge-281/conor-hoekstra/ch-2.bqn b/challenge-281/conor-hoekstra/ch-2.bqn
new file mode 100644
index 0000000000..4289be1dab
--- /dev/null
+++ b/challenge-281/conor-hoekstra/ch-2.bqn
@@ -0,0 +1,16 @@
+# For up to date code:
+# https://github.com/codereport/bqn-code/blob/main/pwc/281-2.bqn
+
+Convert ← 48|-⟜'0'¨
+deltas  ← (⌽¨⊸∾)∾<˘2‿¯2⋈⌜1‿¯1
+IsValid ← ∧´1⊸≤∧8⊸≥
+Moves   ← {IsValid¨⊸/⥊𝕩+⌜deltas}
+
+MinKnightMoves ← {
+    end‿start ← 𝕨 ⋈○Convert 𝕩
+    1 end { ∨´𝕗⊸≡¨Moves 𝕩 ? 𝕨 ; (𝕨+1) 𝕊 Moves 𝕩 } ⟨start⟩
+}
+
+# Tests
+•Show "g2" MinKnightMoves "a8" # 4
+•Show "g2" MinKnightMoves "h2" # 3
-- 
cgit 


From 40e0872043f93838791d288a94b44068bbabfa71 Mon Sep 17 00:00:00 2001
From: Dave Jacoby <jacoby.david@gmail.com>
Date: Mon, 5 Aug 2024 19:13:07 -0400
Subject: DAJ 281

---
 challenge-281/dave-jacoby/blog.txt     |  1 +
 challenge-281/dave-jacoby/perl/ch-1.pl | 22 ++++++++
 challenge-281/dave-jacoby/perl/ch-2.pl | 99 ++++++++++++++++++++++++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 challenge-281/dave-jacoby/blog.txt
 create mode 100644 challenge-281/dave-jacoby/perl/ch-1.pl
 create mode 100644 challenge-281/dave-jacoby/perl/ch-2.pl

diff --git a/challenge-281/dave-jacoby/blog.txt b/challenge-281/dave-jacoby/blog.txt
new file mode 100644
index 0000000000..fd60fc879a
--- /dev/null
+++ b/challenge-281/dave-jacoby/blog.txt
@@ -0,0 +1 @@
+https://jacoby-lpwk.onrender.com/2024/08/05/pawning-things-off-weekly-challenge-281.html
diff --git a/challenge-281/dave-jacoby/perl/ch-1.pl b/challenge-281/dave-jacoby/perl/ch-1.pl
new file mode 100644
index 0000000000..ca81d9bcd6
--- /dev/null
+++ b/challenge-281/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ bitwise fc postderef say signatures state };
+
+my @examples = (qw{ d3 g5 e6 });
+
+for my $example (@examples) {
+    my $output = color_check($example);
+    say <<"END";
+    Input:  \@str = "$example"
+    Output: $output
+END
+}
+
+sub color_check ($input) {
+    my ( $l, $n ) = split //, $input;
+    my @lets = 'a' .. 'h';
+    my %lets = map { $lets[$_] => $_ } 0 .. -1 + scalar @lets;
+    return ( $lets{$l} + ( $n % 2 ) ) % 2 ? 'false' : 'true ';
+}
diff --git a/challenge-281/dave-jacoby/perl/ch-2.pl b/challenge-281/dave-jacoby/perl/ch-2.pl
new file mode 100644
index 0000000000..84a7402b54
--- /dev/null
+++ b/challenge-281/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,99 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use experimental qw{ fc say postderef signatures state };
+
+my @examples = ( # added a couple test entries
+
+    [ 'g2', 'a8' ],
+    [ 'g2', 'h2' ],
+    [ 'a1', 'h8' ],
+    [ 'd5', 'e4' ],
+);
+
+for my $input (@examples) {
+    my $output = knights_move($input);
+    my ( $start, $end ) = $input->@*;
+    say <<"END";
+    Input:  \$start = "$start", \$end = "$end"
+    Output: $output
+END
+}
+
+sub knights_move($input) {
+    my ( $start, $end ) = $input->@*;
+    my $board = {}; # used for display
+    my $done  = {}; # used to track the win
+    my @end   = split //, $end;
+    $board->{ $end[0] }{ $end[1] } = -2;
+    $done->{$end} = 'E';
+
+
+    # these get us from 'a1' to [7,0] and back
+    my @lets = 'a' .. 'h';
+    my %lets = map { $lets[$_] => $_ } 0 .. -1 + scalar @lets;
+    my %stel = reverse %lets;
+
+    my @nums = reverse 1 .. 8;
+    my %nums = map { $nums[$_] => $_ } 0 .. -1 + scalar @nums;
+    my %smun = reverse %nums;
+
+    my @moves = ( [ $start, 0 ] );
+    my @jumps = (
+        [ -1, -2 ], [ -1, 2 ], [ -2, -1 ], [ -2, 1 ],
+        [ 1,  -2 ], [ 1,  2 ], [ 2,  -1 ], [ 2,  1 ],
+    );
+
+    for my $move (@moves) {
+        my ( $space, $depth ) = $move->@*;
+        my ( $l, $n ) = split //, $space;
+        if ( defined $done->{$space} ) {
+            if ( $done->{$space} eq 'E' ) {
+                # display_board($board);
+                return $depth;
+            }
+            next;
+        }
+
+        $board->{$l}{$n} = $depth;
+        $done->{$space} = $depth;
+
+        for my $jump (@jumps) {
+            my ( $i, $j ) = $jump->@*;
+            my $ll = $lets{$l} + $i;
+            my $nn = $nums{$n} + $j;
+
+            if ( $ll >= 0 && $ll <= 7 ) {
+                if ( $nn >= 0 && $nn <= 7 ) {
+                    my $new = join '', $stel{$ll}, $smun{$nn};
+                    push @moves, [ $new, $depth + 1 ];
+                }
+            }
+        }
+    }
+
+    # There's always a way, but I don't like not providing an unaccounted 
+    # case
+    return 'fail';
+}
+
+sub display_board ($board) {
+    my @lets = 'a' .. 'h';
+    my @nums = reverse 1 .. 8;
+    for my $num (@nums) {
+        print qq{$num  };
+        for my $let (@lets) {
+            my $char = '_';
+            if ( defined $board->{$let}{$num} ) {
+                $char =
+                    $board->{$let}{$num} == -2
+                    ? 'E'
+                    : $board->{$let}{$num};
+            }
+            print qq{ [$char] };
+        }
+        say '';
+    }
+    say join '    ', ' ', @lets;
+}
-- 
cgit 


From b029a5cccde12c8c49738508cfa0d003e5856adc Mon Sep 17 00:00:00 2001
From: KjetilS <kjetilskotheim@gmail.com>
Date: Tue, 6 Aug 2024 01:34:57 +0200
Subject: https://theweeklychallenge.org/blog/perl-weekly-challenge-281/

---
 challenge-281/kjetillll/perl/ch-1.pl |  6 ++++++
 challenge-281/kjetillll/perl/ch-2.pl | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 challenge-281/kjetillll/perl/ch-1.pl
 create mode 100644 challenge-281/kjetillll/perl/ch-2.pl

diff --git a/challenge-281/kjetillll/perl/ch-1.pl b/challenge-281/kjetillll/perl/ch-1.pl
new file mode 100644
index 0000000000..cae2900422
--- /dev/null
+++ b/challenge-281/kjetillll/perl/ch-1.pl
@@ -0,0 +1,6 @@
+use strict; use warnings; use Test::More tests=>2;
+
+sub is_light { pop() =~ /^( [aceg][2468] | [bdfh][1357] )$/x }
+
+ok is_light( "d3" ) == 1;
+ok is_light( "g5" ) == 0;
diff --git a/challenge-281/kjetillll/perl/ch-2.pl b/challenge-281/kjetillll/perl/ch-2.pl
new file mode 100644
index 0000000000..6d2836b302
--- /dev/null
+++ b/challenge-281/kjetillll/perl/ch-2.pl
@@ -0,0 +1,26 @@
+use strict; use warnings; use Test::More;
+
+sub knight_steps {
+    #represent the input positions in @_ of the form a1, b2 and so on as
+    #numeric positions instead where the letters a-h becomes 10 20 30 40 50 60 70 80
+    #and concat that with the digit so for example a1 becomes 101, c7 -> 307, h8 -> 808
+
+    my( $from, $to ) = map s/./ 10*ord($&)-960 /er, @_; #convert input as described
+    my @check = ( [$from, 0] );
+    while( my($pos, $steps) = @{ shift @check } ){
+        return $steps if $pos eq $to;
+        push @check,              #push into work list
+            map [$_, $steps+1],   #register new posible jumps
+            grep /[1-8]0[1-8]/,   #don't keep jumps outside board
+            map $pos + $_,        #jump to
+            201,  102,  199,  98, #valid jumps
+           -201, -102, -199, -98;
+    }
+}
+
+ok knight_steps('g2' => 'a8') == 4;
+ok knight_steps('g2' => 'h2') == 3;
+ok knight_steps('h1' => 'a8') == 6;
+ok knight_steps('c3' => 'c4') == 3;
+ok knight_steps('a1' => 'a1') == 0;
+done_testing;
-- 
cgit 


From 39c5867315fd94c62bdf0bef5767247348b1781e Mon Sep 17 00:00:00 2001
From: KjetilS <kjetilskotheim@gmail.com>
Date: Tue, 6 Aug 2024 01:35:25 +0200
Subject: improvement of last weeks answer, uncomplicate it

---
 challenge-280/kjetillll/perl/ch-2.pl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/challenge-280/kjetillll/perl/ch-2.pl b/challenge-280/kjetillll/perl/ch-2.pl
index 904a03eb3f..afc5b87f93 100644
--- a/challenge-280/kjetillll/perl/ch-2.pl
+++ b/challenge-280/kjetillll/perl/ch-2.pl
@@ -2,7 +2,8 @@ use strict; use warnings; use Test::More tests=>3;
 
 sub count {
     local $_ = shift;
-    s/ \| .*? \| //x ? count($_) : y/*//
+    s/ \| .*? \| //xg;
+    y/*//
 }
 
 is count( $$_{input} ) => $$_{output}
-- 
cgit 


From 070329afb38475de9ad40bcadd50ea1672126940 Mon Sep 17 00:00:00 2001
From: Michael Manring <michael@manring>
Date: Tue, 6 Aug 2024 11:21:46 +1000
Subject: pwc281 solution in python

---
 challenge-281/pokgopun/python/ch-1.py | 52 ++++++++++++++++++++++
 challenge-281/pokgopun/python/ch-2.py | 83 +++++++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+)
 create mode 100644 challenge-281/pokgopun/python/ch-1.py
 create mode 100644 challenge-281/pokgopun/python/ch-2.py

diff --git a/challenge-281/pokgopun/python/ch-1.py b/challenge-281/pokgopun/python/ch-1.py
new file mode 100644
index 0000000000..6b74504f58
--- /dev/null
+++ b/challenge-281/pokgopun/python/ch-1.py
@@ -0,0 +1,52 @@
+### https://theweeklychallenge.org/blog/perl-weekly-challenge-281/
+"""
+
+Task 1: Check Color
+
+Submitted by: [47]Mohammad Sajid Anwar
+     __________________________________________________________________
+
+   You are given coordinates, a string that represents the coordinates of
+   a square of the chessboard as shown below:
+
+   Week_281_Task_1
+
+   Write a script to return true if the square is light, and false if the
+   square is dark.
+
+Example 1
+
+Input: $coordinates = "d3"
+Output: true
+
+Example 2
+
+Input: $coordinates = "g5"
+Output: false
+
+Example 3
+
+Input: $coordinates = "e6"
+Output: true
+
+Task 2: Knight’s Move
+"""
+### solution by pokgopun@gmail.com
+
+def checkColor(string: str):
+    return sum(
+            ord(c) for c in string
+            ) % 2 == 1
+
+import unittest
+
+class TestCheckColor(unittest.TestCase):
+    def test(self):
+        for inpt, otpt in {
+                "d3": True,
+                "g5": False,
+                "e6": True,
+                }.items():
+            self.assertEqual(checkColor(inpt),otpt)
+
+unittest.main()
diff --git a/challenge-281/pokgopun/python/ch-2.py b/challenge-281/pokgopun/python/ch-2.py
new file mode 100644
index 0000000000..7e6b5f5807
--- /dev/null
+++ b/challenge-281/pokgopun/python/ch-2.py
@@ -0,0 +1,83 @@
+### https://theweeklychallenge.org/blog/perl-weekly-challenge-281/
+"""
+
+Task 2: Knight’s Move
+
+Submitted by: [48]Peter Campbell Smith
+     __________________________________________________________________
+
+   A Knight in chess can move from its current position to any square two
+   rows or columns plus one column or row away. So in the diagram below,
+   if it starts a S, it can move to any of the squares marked E.
+
+   Write a script which takes a starting position and an ending position
+   and calculates the least number of moves required.
+
+   Week_281_Task_2
+
+Example 1
+
+Input: $start = 'g2', $end = 'a8'
+Ouput: 4
+
+g2 -> e3 -> d5 -> c7 -> a8
+
+Example 2
+
+Input: $start = 'g2', $end = 'h2'
+Ouput: 3
+
+g2 -> e3 -> f1 -> h2
+     __________________________________________________________________
+
+   Last date to submit the solution 23:59 (UK Time) Sunday 11th August
+   2024.
+     __________________________________________________________________
+
+SO WHAT DO YOU THINK ?
+"""
+### solution by pokgopun@gmail.com
+### https://afteracademy.com/blog/knight-on-chessboard/#:~:text=Solution,the%20shape%20of%20an%20L).
+
+def pos2xy(string: str):
+    return ord(string[0])-97, ord(string[1])-49
+
+def xy2pos(x, y):
+    return chr(97+x)+chr(49+y)
+
+def isOnBoard(x, y):
+    return x >=0 and x < 8 and y >= 0 and y < 8
+
+def knightMove(start, end):
+    XYd = ( (-2,-1), (-1,-2), ( 1,-2), ( 2,-1), (-2, 1), (-1, 2), ( 1, 2), ( 2, 1) )
+    XYa = tuple([None for y in range(8)] for x in range(8))
+    x0, y0 = pos2xy(start)
+    x1, y1 = pos2xy(end)
+    #XYa[x0][y0] = 0
+    XYa[x0][y0] = ""
+    XYq = [(x0, y0)]
+    while len(XYq) > 0:
+        x, y = XYq.pop(0)
+        if (x,y) == (x1,y1):
+            #return XYa[x][y]
+            print(XYa[x][y]+end,"=>",int(len(XYa[x][y])/2))
+            return int(len(XYa[x][y])/2)
+        for dx, dy in XYd:
+            xn, yn = x + dx, y + dy
+            if isOnBoard(xn, yn) and XYa[xn][yn] is None:
+                #XYa[xn][yn] = XYa[x][y] + 1
+                XYa[xn][yn] = XYa[x][y] + xy2pos(x,y)
+                XYq.append((xn,yn))
+    return -1
+
+import unittest
+
+class TestKnightMove(unittest.TestCase):
+    def test(self):
+        for (start,end), count in {
+                ('g2', 'a8'): 4,
+                ('g2', 'h2'): 3,
+                }.items():
+            self.assertEqual(knightMove(start, end), count)
+
+unittest.main()
-- 
cgit 


From 4b08f96f7df8de14e0c77b7fabbde2ade95718d2 Mon Sep 17 00:00:00 2001
From: Packy Anderson <packy@cpan.org>
Date: Mon, 5 Aug 2024 23:00:40 -0400
Subject: Challenge 281 solutions by Packy Anderson

  * Raku that maybe looks like Raku, but mostly like Perl
  * Perl
  * Python that definitely looks like Perl
  * Elixir (Task 1 only so far)

1 Blog post
---
 challenge-281/packy-anderson/README.md         |   2 +-
 challenge-281/packy-anderson/blog.txt          |   1 +
 challenge-281/packy-anderson/blog/graphviz.dot |  59 ++++++++++++++++++
 challenge-281/packy-anderson/blog/graphviz.png | Bin 0 -> 468918 bytes
 challenge-281/packy-anderson/elixir/ch-1.exs   |  31 ++++++++++
 challenge-281/packy-anderson/elixir/ch-2.exs   |  20 ++++++
 challenge-281/packy-anderson/perl/ch-1.pl      |  25 ++++++++
 challenge-281/packy-anderson/perl/ch-2.pl      |  81 +++++++++++++++++++++++++
 challenge-281/packy-anderson/python/ch-1.py    |  23 +++++++
 challenge-281/packy-anderson/python/ch-2.py    |  77 +++++++++++++++++++++++
 challenge-281/packy-anderson/raku/ch-1.raku    |  25 ++++++++
 challenge-281/packy-anderson/raku/ch-2.raku    |  81 +++++++++++++++++++++++++
 12 files changed, 424 insertions(+), 1 deletion(-)
 create mode 100644 challenge-281/packy-anderson/blog.txt
 create mode 100644 challenge-281/packy-anderson/blog/graphviz.dot
 create mode 100644 challenge-281/packy-anderson/blog/graphviz.png
 create mode 100755 challenge-281/packy-anderson/elixir/ch-1.exs
 create mode 100755 challenge-281/packy-anderson/elixir/ch-2.exs
 create mode 100755 challenge-281/packy-anderson/perl/ch-1.pl
 create mode 100755 challenge-281/packy-anderson/perl/ch-2.pl
 create mode 100755 challenge-281/packy-anderson/python/ch-1.py
 create mode 100755 challenge-281/packy-anderson/python/ch-2.py
 create mode 100755 challenge-281/packy-anderson/raku/ch-1.raku
 create mode 100755 challenge-281/packy-anderson/raku/ch-2.raku

diff --git a/challenge-281/packy-anderson/README.md b/challenge-281/packy-anderson/README.md
index 7974906632..69be440f4b 100644
--- a/challenge-281/packy-anderson/README.md
+++ b/challenge-281/packy-anderson/README.md
@@ -22,4 +22,4 @@
 
 ## Blog Post
 
-[Perl Weekly Challenge: Appear Twice, Count Once](https://packy.dardan.com/b/P_)
+[Perl Weekly Challenge: The Ultimate Test of Cerebral Fitness](https://packy.dardan.com/b/Pd)
diff --git a/challenge-281/packy-anderson/blog.txt b/challenge-281/packy-anderson/blog.txt
new file mode 100644
index 0000000000..84c5dd54ff
--- /dev/null
+++ b/challenge-281/packy-anderson/blog.txt
@@ -0,0 +1 @@
+https://packy.dardan.com/b/Pd
\ No newline at end of file
diff --git a/challenge-281/packy-anderson/blog/graphviz.dot b/challenge-281/packy-anderson/blog/graphviz.dot
new file mode 100644
index 0000000000..5651258a6a
--- /dev/null
+++ b/challenge-281/packy-anderson/blog/graphviz.dot
@@ -0,0 +1,59 @@
+digraph G {
+  node [style=filled]
+  edge [style=dashed]
+  g2 -> e3 -> c4 -> b6 -> a8  [style=solid, color=red];
+  g2 -> e1
+  g2 -> f4
+  g2 -> h4
+  e1 -> c2
+  e1 -> d3
+  e1 -> f3
+  e3 -> d1
+  e3 -> d5
+  e3 -> g4
+  e3 -> f1
+  e3 -> f5
+  f4 -> e2
+  f4 -> e6
+  f4 -> h3
+  f4 -> h5
+  f4 -> g6
+  c2 -> a1
+  c2 -> a3
+  c2 -> b4
+  c2 -> d4
+  d3 -> b2
+  d3 -> c1
+  d3 -> c5
+  d3 -> f2
+  d3 -> e5
+  f3 -> d2
+  f3 -> h2
+  f3 -> g1
+  f3 -> g5
+  c4 -> a5
+  c4 -> d6
+  d1 -> c3
+  d5 -> c7
+  d5 -> f6
+  d5 -> e7
+  g4 -> h6
+  f1 -> g3
+  f5 -> g7
+  e6 -> d8
+  e6 -> f8
+  g6 -> h8
+  a1 -> b3
+  a3 -> b1
+  a3 -> b5
+  b4 -> a2
+  b4 -> a6
+  b4 -> c6
+  b2 -> a4
+  c5 -> b7
+  c5 -> e4
+  c5 -> d7
+  f2 -> h1
+  e5 -> f7
+  g5 -> h7
+}
\ No newline at end of file
diff --git a/challenge-281/packy-anderson/blog/graphviz.png b/challenge-281/packy-anderson/blog/graphviz.png
new file mode 100644
index 0000000000..a0ec8a2060
Binary files /dev/null and b/challenge-281/packy-anderson/blog/graphviz.png differ
diff --git a/challenge-281/packy-anderson/elixir/ch-1.exs b/challenge-281/packy-anderson/elixir/ch-1.exs
new file mode 100755
index 0000000000..ebf52874c3
--- /dev/null
+++ b/challenge-281/packy-anderson/elixir/ch-1.exs
@@ -0,0 +1,31 @@
+#!/usr/bin/env elixir
+
+defmodule PWC do
+  require Integer
+
+  def isLight(coordinates) do
+    letter = String.first(coordinates)
+    {num, _} = Integer.parse(String.last(coordinates))
+    cond do
+      String.contains?("aceg", letter)
+        and Integer.is_even(num) -> "true"
+      String.contains?("bdfh", letter)
+        and Integer.is_odd(num)  -> "true"
+      true -> "false"
+    end
+  end
+
+  def solution(coordinates) do
+    IO.puts("Input: $coordinates = \"#{coordinates}\"")
+    IO.puts("Output: " <> isLight(coordinates) )
+  end
+end
+
+IO.puts("Example 1:")
+PWC.solution("d3")
+
+IO.puts("\nExample 2:")
+PWC.solution("g5")
+
+IO.puts("\nExample 3:")
+PWC.solution("e6")
diff --git a/challenge-281/packy-anderson/elixir/ch-2.exs b/challenge-281/packy-anderson/elixir/ch-2.exs
new file mode 100755
index 0000000000..04b5c8529b
--- /dev/null
+++ b/challenge-281/packy-anderson/elixir/ch-2.exs
@@ -0,0 +1,20 @@
+#!/usr/bin/env elixir
+
+defmodule PWC do
+
+  def solution(ints) do
+    IO.puts("Input: @ints = (" <> Enum.join(ints, ", ") <> ")")
+    {sign, explain} = PWC.productSign(ints)
+    IO.puts("Output: " <> to_string(sign) )
+    IO.puts("\n" <> explain)
+  end
+end
+
+IO.puts("Example 1:")
+PWC.solution()
+
+IO.puts("\nExample 2:")
+PWC.solution()
+
+IO.puts("\nExample 3:")
+PWC.solution()
diff --git a/challenge-281/packy-anderson/perl/ch-1.pl b/challenge-281/packy-anderson/perl/ch-1.pl
new file mode 100755
index 0000000000..ff595d7c57
--- /dev/null
+++ b/challenge-281/packy-anderson/perl/ch-1.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+use v5.40;
+
+sub isLight($coordinates) {
+  my ($letter, $num) = split //, $coordinates;
+  return (
+    ( ($letter =~ /[aceg]/) && ($num % 2 == 0) )
+    ||
+    ( ($letter =~ /[bdfh]/) && ($num % 2 == 1) )
+  ) ? 'true' : 'false';
+}
+
+sub solution($coordinates) {
+  say qq/Input: \$coordinates = "$coordinates"/;
+  say 'Output: ' . isLight($coordinates);
+}
+
+say "Example 1:";
+solution("d3");
+
+say "\nExample 2:";
+solution("g5");
+
+say "\nExample 3:";
+solution("e6");
diff --git a/challenge-281/packy-anderson/perl/ch-2.pl b/challenge-281/packy-anderson/perl/ch-2.pl
new file mode 100755
index 0000000000..92eeb1cbd4
--- /dev/null
+++ b/challenge-281/packy-anderson/perl/ch-2.pl
@@ -0,0 +1,81 @@
+#!/usr/bin/env perl
+use v5.40;
+
+my @knightMoveList = (
+  [-2, -1], [-2, +1], [-1, -2], [-1, +2],
+  [+2, -1], [+2, +1], [+1, -2], [+1, +2],
+);
+
+sub knightMoves($coordinates) {
+  my ($letter, $num) = split //, $coordinates;
+  my @endpoints;
+  foreach my $colRow ( @knightMoveList ) {
+    my ($col, $row) = @$colRow;
+    my $newcol = chr(ord($letter) + $col);
+    next unless $newcol ge "a" && $newcol le "h";
+    my $newrow = $num + $row;
+    next unless 1 <= $newrow <= 8;
+    push @endpoints, ($newcol . $newrow);
+  }
+  return @endpoints;
+}
+
+sub leastMoves($start, $end) {
+  # trivial case: we're already at the end point
+  return ( 0, $end ) if $start eq $end;
+
+  # Ok, we're going to need to search for a solution.
+
+  # Keep track of how many moves it takes to get to
+  # a particular position, starting at $start
+  my %moves = ( $start => 0 );
+
+  # also keep track of the path to get there
+  my %path_to = ( $start => $start );
+
+  # make a queue of starting points
+  my @queue = ( $start );
+
+  while ( @queue ) {
+    $start = shift @queue;
+
+    # figure out the valid moves that we haven't been to yet
+    my @endpoints = grep {
+      ! exists $path_to{$_}
+    } knightMoves($start);
+
+    foreach my $next ( @endpoints ) {
+      # build the path to the next endpoint
+      $path_to{$next} = $path_to{$start} . " -> $next";
+
+      # increment the number of moves it takes to get there
+      $moves{$next} = $moves{$start} + 1;
+
+      # have we arrived at our destination
+      return ( $moves{$next}, $path_to{$next} ) if $next eq $end;
+
+      # no? then push this space onto our processing queue
+      push @queue, $next;
+    }
+  }
+
+  # we can't get there from here!
+  # (only possible when the chessboard is an odd size)
+  return ( -1, "no path found" );
+}
+
+sub solution($start, $end) {
+  say qq/Input: \$start = '$start', \$end = '$end'/;
+  my ($count, $moves) = leastMoves($start, $end);
+  say 'Output: ' . $count;
+  say "\n$moves\n";
+}
+
+say "Example 1:";
+solution('g2', 'a8');
+
+say "\nExample 2:";
+solution('g2', 'h2');
+
+say "\nExample 3:";
+solution('a1', 'h8');
diff --git a/challenge-281/packy-anderson/python/ch-1.py b/challenge-281/packy-anderson/python/ch-1.py
new file mode 100755
index 0000000000..a327de57b8
--- /dev/null
+++ b/challenge-281/packy-anderson/python/ch-1.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+def isLight(coordinates):
+  letter = coordinates[0:1]
+  num = int(coordinates[1:])
+  return (
+     ( (letter in "aceg") and (num % 2 == 0) )
+     or
+     ( (letter in "bdfh") and (num % 2 == 1) )
+  )
+
+def solution(coordinates):
+    print(f'Input: $coordinates = "{coordinates}"')
+    print(f'Output: {isLight(coordinates)}')
+
+print('Example 1:')
+solution("d3")
+
+print('\nExample 2:')
+solution("g5")
+
+print('\nExample 3:')
+solution("e6")
diff --git a/challenge-281/packy-anderson/python/ch-2.py b/challenge-281/packy-anderson/python/ch-2.py
new file mode 100755
index 0000000000..f1b8803a71
--- /dev/null
+++ b/challenge-281/packy-anderson/python/ch-2.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python
+
+knightMoveList = [
+  [-2, -1], [-2, +1], [-1, -2], [-1, +2],
+  [+2, -1], [+2, +1], [+1, -2], [+1, +2],
+]
+
+def knightMoves(coordinates):
+  letter = coordinates[0:1]
+  num = int(coordinates[1:])
+  endpoints = []
+  for colRow in knightMoveList:
+    col, row = colRow
+    newcol = chr(ord(letter) + col)
+    if "a" <= newcol <= "h":
+      newrow = num + row
+      if 1 <= newrow <= 8:
+        endpoints.append(newcol + str(newrow))
+  return endpoints
+
+
+def leastMoves(start, end):
+  # trivial case: we're already at the end point
+  if start == end:
+      return ( 0, end )
+
+  # Ok, we're going to need to search for a solution.
+
+  # Keep track of how many moves it takes to get to
+  # a particular position, starting at $start
+  moves = { start: 0 }
+
+  # also keep track of the path to get there
+  path_to = { start: start }
+
+  # make a queue of starting points
+  queue = [ start ]
+
+  while ( queue ):
+    start = queue.pop(0)
+
+    # figure out the valid moves that we haven't been to yet
+    endpoints = [
+      m for m in knightMoves(start) if m not in path_to
+    ]
+
+    for next in endpoints:
+      # build the path to the next endpoint
+      path_to[next] = f'{path_to[start]} -> {next}'
+
+      # increment the number of moves it takes to get there
+      moves[next] = moves[start] + 1
+
+      # have we arrived at our destination
+      if next == end:
+        return ( moves[next], path_to[next] )
+
+      # no? then push this space onto our processing queue
+      queue.append(next)
+
+  # we can't get there from here!
+  # (only possible when the chessboard is an odd size)
+  return ( -1, "no path found" )
+
+def solution(start, end):
+    print(f'Input: $start = \'{start}\', $end = \'{end}\'')
+    count, moves = leastMoves(start, end)
+    print(f'Output: {count}\n\n{moves}\n')
+
+print('Example 1:')
+solution('g2', 'a8')
+
+print('\nExample 2:')
+solution('g2', 'h2')
+
+print('\nExample 3:')
+solution('a1', 'h8')
diff --git a/challenge-281/packy-anderson/raku/ch-1.raku b/challenge-281/packy-anderson/raku/ch-1.raku
new file mode 100755
index 0000000000..44ea131900
--- /dev/null
+++ b/challenge-281/packy-anderson/raku/ch-1.raku
@@ -0,0 +1,25 @@
+#!/usr/bin/env raku
+use v6;
+
+sub isLight($coordinates) {
+  my ($letter, $num) = $coordinates.comb;
+  return (
+    $letter.match(/<[aceg]>/) && ($num %% 2)
+    ||
+    $letter.match(/<[bdfh]>/) && !($num %% 2)
+  ) ?? 'true' !! 'false';
+}
+
+sub solution($coordinates) {
+  say qq/Input: \$coordinates = "$coordinates"/;
+  say 'Output: ' ~ isLight($coordinates);
+}
+
+say "Example 1:";
+solution("d3");
+
+say "\nExample 2:";
+solution("g5");
+
+say "\nExample 3:";
+solution("e6");
diff --git a/challenge-281/packy-anderson/raku/ch-2.raku b/challenge-281/packy-anderson/raku/ch-2.raku
new file mode 100755
index 0000000000..4ab5b7f4b1
--- /dev/null
+++ b/challenge-281/packy-anderson/raku/ch-2.raku
@@ -0,0 +1,81 @@
+#!/usr/bin/env raku
+use v6;
+
+my @knightMoveList = (
+  (-2, -1), (-2, +1), (-1, -2), (-1, +2),
+  (+2, -1), (+2, +1), (+1, -2), (+1, +2),
+);
+
+sub knightMoves($coordinates) {
+  my ($letter, $num) = $coordinates.comb;
+  my @endpoints;
+  for @knightMoveList -> @colRow {
+    my ($col, $row) = @colRow;
+    my $newcol = ($letter.ord + $col).chr;
+    next unless $newcol ge "a" && $newcol le "h";
+    my $newrow = $num + $row;
+    next unless 1 <= $newrow <= 8;
+    @endpoints.push($newcol ~ $newrow);
+  }
+  return @endpoints;
+}
+
+sub leastMoves($start is copy, $end) {
+  # trivial case: we're already at the end point
+  return ( 0, $end ) if $start eq $end;
+
+  # Ok, we're going to need to search for a solution.
+
+  # Keep track of how many moves it takes to get to
+  # a particular position, starting at $start
+  my %moves = ( $start => 0 );
+
+  # also keep track of the path to get there
+  my %path_to = ( $start => $start );
+
+  # make a queue of starting points
+  my @queue = ( $start );
+
+  while ( @queue ) {
+    $start = @queue.shift;
+
+    # figure out the valid moves that we haven't been to yet
+    my @endpoints = knightMoves($start).grep({
+      %path_to{$_}:!exists
+    });
+
+    for @endpoints -> $next {
+      # build the path to the next endpoint
+      %path_to{$next} = %path_to{$start} ~ " -> $next";
+
+      # increment the number of moves it takes to get there
+      %moves{$next} = %moves{$start} + 1;
+
+      # have we arrived at our destination
+      return ( %moves{$next}, %path_to{$next} ) if $next eq $end;
+
+      # no? then push this space onto our processing queue
+      @queue.push: $next;
+    }
+  }
+
+  # we can't get there from here!
+  # (only possible when the chessboard is an odd size)
+  return ( -1, "no path found" );
+}
+
+sub solution($start, $end) {
+  say qq/Input: \$start = '$start', \$end = '$end'/;
+  my ($count, $moves) = leastMoves($start, $end);
+  say 'Output: ' ~ $count;
+  say "\n$moves\n";
+}
+
+say "Example 1:";
+solution('g2', 'a8');
+
+say "\nExample 2:";
+solution('g2', 'h2');
+
+say "\nExample 3:";
+solution('a1', 'h8');
-- 
cgit 


From 24a5e6524c7a1548a7cd66e4696e0dec64929523 Mon Sep 17 00:00:00 2001
From: Tymoteusz Moryto <tymek24m@gmail.com>
Date: Tue, 6 Aug 2024 09:59:49 +0200
Subject: solutions for week 281 in uiua

---
 challenge-281/pieviero/ch-1.ua |  4 ++++
 challenge-281/pieviero/ch-2.ua | 14 ++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 challenge-281/pieviero/ch-1.ua
 create mode 100644 challenge-281/pieviero/ch-2.ua

diff --git a/challenge-281/pieviero/ch-1.ua b/challenge-281/pieviero/ch-1.ua
new file mode 100644
index 0000000000..d12fbc8f59
--- /dev/null
+++ b/challenge-281/pieviero/ch-1.ua
@@ -0,0 +1,4 @@
+CheckColor ← ¬◿2+⊓-⋕@a°⊂
+CheckColor "d3"
+CheckColor "g5"
+CheckColor "e6"
diff --git a/challenge-281/pieviero/ch-2.ua b/challenge-281/pieviero/ch-2.ua
new file mode 100644
index 0000000000..bc1e37e89a
--- /dev/null
+++ b/challenge-281/pieviero/ch-2.ua
@@ -0,0 +1,14 @@
+Diffs ← [[1 2] [2 1]
+         [1 ¯2] [2 ¯1]
+         [¯1 2] [¯2 1]
+         [¯1 ¯2] [¯2 ¯1]]
+Convert ← ⍜°⊂(⊓-⋕-1@a)
+IsValid ← ×⊓>≤0,8
+FilterMoves ← ▽≡/×IsValid.
+ApplyDiffs ← +Diffs¤
+
+# ? end start
+KnightsMove ← ◌◌⍢(⊙⊙(+1)◴FilterMoves☇1≡ApplyDiffs|=0/+∊:,,)⊙⊙(0)¤:∩Convert
+KnightsMove "a8" "g2"
+KnightsMove "h2" "g2"
+
-- 
cgit 


From 8bd7329fb0dec9a57bb33590877839ac69728b82 Mon Sep 17 00:00:00 2001
From: Michael Manring <michael@manring>
Date: Tue, 6 Aug 2024 18:59:36 +1000
Subject: pwc281 solution in go

---
 challenge-281/pokgopun/go/ch-1.go |  60 +++++++++++++++++++++
 challenge-281/pokgopun/go/ch-2.go | 109 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 169 insertions(+)
 create mode 100644 challenge-281/pokgopun/go/ch-1.go
 create mode 100644 challenge-281/pokgopun/go/ch-2.go

diff --git a/challenge-281/pokgopun/go/ch-1.go b/challenge-281/pokgopun/go/ch-1.go
new file mode 100644
index 0000000000..7a10b39811
--- /dev/null
+++ b/challenge-281/pokgopun/go/ch-1.go
@@ -0,0 +1,60 @@
+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-281/
+/*#
+
+Task 1: Check Color
+
+Submitted by: [47]Mohammad Sajid Anwar
+     __________________________________________________________________
+
+   You are given coordinates, a string that represents the coordinates of
+   a square of the chessboard as shown below:
+
+   Week_281_Task_1
+
+   Write a script to return true if the square is light, and false if the
+   square is dark.
+
+Example 1
+
+Input: $coordinates = "d3"
+Output: true
+
+Example 2
+
+Input: $coordinates = "g5"
+Output: false
+
+Example 3
+
+Input: $coordinates = "e6"
+Output: true
+
+Task 2: Knight’s Move
+#*/
+//# solution by pokgopun@gmail.com
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func checkColor(str string) bool {
+	return ((str[0] % 2) + (str[1] % 2)) == 1
+}
+
+func main() {
+	for _, data := range []struct {
+		input  string
+		output bool
+	}{
+		{"d3", true},
+		{"g5", false},
+		{"e6", true},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(checkColor(data.input), data.output)) // blank if ok, otherwise show the difference
+	}
+}
diff --git a/challenge-281/pokgopun/go/ch-2.go b/challenge-281/pokgopun/go/ch-2.go
new file mode 100644
index 0000000000..9f4f229646
--- /dev/null
+++ b/challenge-281/pokgopun/go/ch-2.go
@@ -0,0 +1,109 @@
+//# https://theweeklychallenge.org/blog/perl-weekly-challenge-281/
+/*#
+
+Task 2: Knight’s Move
+
+Submitted by: [48]Peter Campbell Smith
+     __________________________________________________________________
+
+   A Knight in chess can move from its current position to any square two
+   rows or columns plus one column or row away. So in the diagram below,
+   if it starts a S, it can move to any of the squares marked E.
+
+   Write a script which takes a starting position and an ending position
+   and calculates the least number of moves required.
+
+   Week_281_Task_2
+
+Example 1
+
+Input: $start = 'g2', $end = 'a8'
+Ouput: 4
+
+g2 -> e3 -> d5 -> c7 -> a8
+
+Example 2
+
+Input: $start = 'g2', $end = 'h2'
+Ouput: 3
+
+g2 -> e3 -> f1 -> h2
+     __________________________________________________________________
+
+   Last date to submit the solution 23:59 (UK Time) Sunday 11th August
+   2024.
+     __________________________________________________________________
+
+SO WHAT DO YOU THINK ?
+#*/
+//# solution by pokgopun@gmail.com
+// https://afteracademy.com/blog/knight-on-chessboard/#:~:text=Solution,the%20shape%20of%20an%20L).
+
+package main
+
+import (
+	"io"
+	"os"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+type position struct {
+	x, y int
+}
+
+func newPosition(label string) position {
+	return position{int(label[0]) - 96, int(label[1]) - 48}
+}
+
+func (pt position) String() string {
+	return string([]byte{byte(pt.x) + 96, byte(pt.y) + 48})
+}
+
+type data struct {
+	count   int
+	visited bool
+}
+
+type board [8][8]data
+
+func (bd board) contains(p position) bool {
+	return p.x >= 1 && p.x <= 8 && p.y >= 1 && p.y <= 8
+}
+
+func knightMove(start, end string) int {
+	var bd board
+	p0 := newPosition(start)
+	p1 := newPosition(end)
+	queue := []position{p0}
+	bd[p0.x-1][p0.y-1] = data{visited: true}
+	dx := [8]int{-2, -1, 1, 2, -2, -1, 1, 2}
+	dy := [8]int{-1, -2, -2, -1, 1, 2, 2, 1}
+	for len(queue) > 0 {
+		p := queue[0]
+		queue = queue[1:]
+		if p.x == p1.x && p.y == p1.y {
+			return bd[p.x-1][p.y-1].count
+		}
+		for i := 0; i < 8; i++ {
+			pn := position{p.x + dx[i], p.y + dy[i]}
+			if bd.contains(pn) && !bd[pn.x-1][pn.y-1].visited {
+				bd[pn.x-1][pn.y-1] = data{visited: true, count: bd[p.x-1][p.y-1].count + 1}
+				queue = append(queue, pn)
+			}
+		}
+	}
+	return -1
+}
+
+func main() {
+	for _, data := range []struct {
+		start, end string
+		count      int
+	}{
+		{"g2", "a8", 4},
+		{"g2", "h2", 3},
+	} {
+		io.WriteString(os.Stdout, cmp.Diff(knightMove(data.start, data.end), data.count)) // blank if ok, otherwise show the difference
+	}
+}
-- 
cgit 


From 4628d1d540ae4e64ef1919b57437bce2f962248b Mon Sep 17 00:00:00 2001
From: Mohammad Sajid Anwar <mohammad.anwar@yahoo.com>
Date: Tue, 6 Aug 2024 10:05:21 +0100
Subject: - Added solutions by Conor Hoekstra. - Added solutions by Thomas
 Kohler. - Added solutions by W. Luis Mochan. - Added solutions by Kjetil
 Skotheim. - Added solutions by Dave Jacoby. - Added solutions by Packy
 Anderson. - Added solutions by Feng Chang. - Added solutions by Tymoteusz
 Moryto. - Added solutions by PokGoPun.

---
 stats/pwc-current.json                    | 266 +++++++---
 stats/pwc-language-breakdown-2019.json    | 320 ++++++------
 stats/pwc-language-breakdown-2020.json    | 770 ++++++++++++++---------------
 stats/pwc-language-breakdown-2021.json    | 414 ++++++++--------
 stats/pwc-language-breakdown-2022.json    | 782 ++++++++++++++---------------
 stats/pwc-language-breakdown-2023.json    | 784 +++++++++++++++---------------
 stats/pwc-language-breakdown-2024.json    | 500 +++++++++----------
 stats/pwc-language-breakdown-summary.json |  76 +--
 stats/pwc-leaders.json                    | 766 ++++++++++++++---------------
 stats/pwc-summary-1-30.json               | 114 ++---
 stats/pwc-summary-121-150.json            | 108 ++--
 stats/pwc-summary-151-180.json            | 116 ++---
 stats/pwc-summary-181-210.json            | 106 ++--
 stats/pwc-summary-211-240.json            | 100 ++--
 stats/pwc-summary-241-270.json            |  50 +-
 stats/pwc-summary-271-300.json            |  48 +-
 stats/pwc-summary-301-330.json            |  42 +-
 stats/pwc-summary-31-60.json              |  96 ++--
 stats/pwc-summary-61-90.json              | 102 ++--
 stats/pwc-summary-91-120.json             |  38 +-
 stats/pwc-summary.json                    |  60 +--
 stats/pwc-yearly-language-summary.json    | 146 +++---
 22 files changed, 2957 insertions(+), 2847 deletions(-)

diff --git a/stats/pwc-current.json b/stats/pwc-current.json
index 4e0ea5448a..153a1f7fac 100644
--- a/stats/pwc-current.json
+++ b/stats/pwc-current.json
@@ -1,103 +1,57 @@
 {
-   "yAxis" : {
-      "title" : {
-         "text" : "Total Solutions"
-      }
-   },
-   "xAxis" : {
-      "type" : "category"
-   },
-   "plotOptions" : {
-      "series" : {
-         "borderWidth" : 0,
-         "dataLabels" : {
-            "format" : "{point.y}",
-            "enabled" : 1
-         }
-      }
+   "title" : {
+      "text" : "The Weekly Challenge - 281"
    },
    "legend" : {
       "enabled" : 0
    },
-   "series" : [
-      {
-         "data" : [
-            {
-               "y" : 2,
-               "name" : "Alexander Karelas",
-               "drilldown" : "Alexander Karelas"
-            },
-            {
-               "y" : 2,
-               "name" : "David Ferrone",
-               "drilldown" : "David Ferrone"
-            },
-            {
-               "y" : 2,
-               "name" : "E. Choroba",
-               "drilldown" : "E. Choroba"
-            },
-            {
-               "drilldown" : "Jan Krnavek",
-               "name" : "Jan Krnavek",
-               "y" : 2
-            },
-            {
-               "drilldown" : "Laurent Rosenfeld",
-               "y" : 3,
-               "name" : "Laurent Rosenfeld"
-            },
-            {
-               "drilldown" : "Mariano Ortega",
-               "y" : 2,
-               "name" : "Mariano Ortega"
-            },
-            {
-               "drilldown" : "Mark Anderson",
-               "y" : 2,
-               "name" : "Mark Anderson"
-            }
-         ],
-         "colorByPoint" : 1,
-         "name" : "The Weekly Challenge - 281"
-      }
-   ],
    "chart" : {
       "type" : "column"
    },
-   "tooltip" : {
-      "pointFormat" : "<span style='color:{point.color}'>{point.name}</span>: <b>{point.y:f}</b><br/>",
-      "followPointer" : 1,
-      "headerFormat" : "<span style='font-size:11px'>{series.name}</span><br/>"
-   },
-   "title" : {
-      "text" : "The Weekly Challenge - 281"
+   "yAxis" : {
+      "title" : {
+         "text" : "Total Solutions"
+      }
    },
    "drilldown" : {
       "series" : [
          {
-            "id" : "Alexander Karelas",
             "data" : [
                [
                   "Perl",
                   2
                ]
             ],
-            "name" : "Alexander Karelas"
+            "name" : "Alexander Karelas",
+            "id" : "Alexander Karelas"
+         },
+         {
+            "data" : [
+               [
+                  "Perl",
+                  2
+               ],
+               [
+                  "Blog",
+                  1
+               ]
+            ],
+            "name" : "Dave Jacoby",
+            "id" : "Dave Jacoby"
          },
          {
-            "name" : "David Ferrone",
             "data" : [
                [
                   "Perl",
                   2
                ]
             ],
-            "id" : "David Ferrone"
+            "id" : "David Ferrone",
+            "name" : "David Ferrone"
          },
          {
-            "name" : "E. Choroba",
             "id" : "E. Choroba",
+            "name" : "E. Choroba",
             "data" : [
                [
                   "Perl",
@@ -106,17 +60,36 @@
             ]
          },
          {
+            "data" : [
+               [
+                  "Raku",
+                  2
+               ]
+            ],
+            "name" : "Feng Chang",
+            "id" : "Feng Chang"
+         },
+         {
+            "id" : "Jan Krnavek",
             "name" : "Jan Krnavek",
             "data" : [
                [
                   "Raku",
                   2
                ]
+            ]
+         },
+         {
+            "data" : [
+               [
+                  "Perl",
+                  2
+               ]
             ],
-            "id" : "Jan Krnavek"
+            "name" : "Kjetil Skotheim",
+            "id" : "Kjetil Skotheim"
          },
          {
-            "id" : "Laurent Rosenfeld",
             "data" : [
                [
                   "Perl",
@@ -131,6 +104,7 @@
                   1
                ]
             ],
+            "id" : "Laurent Rosenfeld",
             "name" : "Laurent Rosenfeld"
          },
          {
@@ -140,22 +114,158 @@
                   2
                ]
             ],
-            "id" : "Mariano Ortega",
-            "name" : "Mariano Ortega"
+            "name" : "Mariano Ortega",
+            "id" : "Mariano Ortega"
          },
          {
+            "data" : [
+               [
+                  "Raku",
+                  2
+               ]
+            ],
             "name" : "Mark Anderson",
-            "id" : "Mark Anderson",
+            "id" : "Mark Anderson"
+         },
+         {
             "data" : [
+               [
+                  "Perl",
+                  2
+               ],
                [
                   "Raku",
                   2
+               ],
+               [
+                  "Blog",
+                  1
                ]
-            ]
+            ],
+            "name" : "Packy Anderson",
+            "id" : "Packy Anderson"
+         },
+         {
+            "data" : [
+               [
+                  "Perl",
+                  2
+               ],
+               [
+                  "Blog",
+                  2
+               ]
+            ],
+            "name" : "Thomas Kohler",
+            "id" : "Thomas Kohler"
+         },
+         {
+            "data" : [
+               [
+                  "Perl",
+                  2
+               ],
+               [
+                  "Blog",
+                  1
+               ]
+            ],
+            "name" : "W. Luis Mochan",
+            "id" : "W. Luis Mochan"
          }
       ]
    },
    "subtitle" : {
-      "text" : "[Champions: 7] Last updated at 2024-08-05 19:01:15 GMT"
+      "text" : "[Champions: 13] Last updated at 2024-08-06 09:04:30 GMT"
+   },
+   "tooltip" : {
+      "headerFormat" : "<span style='font-size:11px'>{series.name}</span><br/>",
+      "followPointer" : 1,
+      "pointFormat" : "<span style='color:{point.color}'>{point.name}</span>: <b>{point.y:f}</b><br/>"
+   },
+   "xAxis" : {
+      "type" : "category"
+   },
+   "series" : [
+      {
+         "name" : "The Weekly Challenge - 281",
+         "colorByPoint" : 1,
+         "data" : [
+            {
+               "y" : 2,
+               "drilldown" : "Alexander Karelas",
+               "name" : "Alexander Karelas"
+            },
+            {
+               "name" : "Dave Jacoby",
+               "drilldown" : "Dave Jacoby",
+               "y" : 3
+            },
+            {
+               "y" : 2,
+               "drilldown" : "David Ferrone",
+               "name" : "David Ferrone"
+            },
+            {
+               "drilldown" : "E. Choroba",
+               "name" : "E. Choroba",
+               "y" : 2
+            },
+            {
+               "y" : 2,
+               "name" : "Feng Chang",
+               "drilldown" : "Feng Chang"
+            },
+            {
+               "y" : 2,
+               "name" : "Jan Krnavek",
+               "drilldown" : "Jan Krnavek"
+            },
+            {
+               "drilldown" : "Kjetil Skotheim",
+               "name" : "Kjetil Skotheim",
+               "y" : 2
+            },
+            {
+               "drilldown" : "Laurent Rosenfeld",
+               "name" : "Laurent Rosenfeld",
+               "y" : 3
+            },
+            {
+               "drilldown" : "Mariano Ortega",
+               "name" : "Mariano Ortega",
+               "y" : 2
+            },
+            {
+               "y" : 2,
+               "name" : "Mark Anderson",
+               "drilldown" : "Mark Anderson"
+            },
+            {
+               "y" : 5,
+               "drilldown" : "Packy Anderson",
+               "name" : "Packy Anderson"
+            },
+            {
+               "y" : 4,
+               "name" : "Thomas Kohler",
+               "drilldown" : "Thomas Kohler"
+            },
+            {
+               "y" : 3,
+               "name" : "W. Luis Mochan",
+               "drilldown" : "W. Luis Mochan"
+            }
+         ]
+      }
+   ],
+   "plotOptions" : {
+      "series" : {
+         "borderWidth" : 0,
+         "dataLabels" : {
+            "enabled" : 1,
+            "format" : "{point.y}"
+         }
+      }
    }
 }
diff --git a/stats/pwc-language-breakdown-2019.json b/stats/pwc-language-breakdown-2019.json
index c3d8544f7d..d68e38e212 100644
--- a/stats/pwc-language-breakdown-2019.json
+++ b/stats/pwc-language-breakdown-2019.json
@@ -1,14 +1,10 @@
 {
-   "chart" : {
-      "type" : "column"
-   },
-   "subtitle" : {
-      "text" : "Click the columns to drilldown the language breakdown. Last updated at 2024-08-05 19:01:15 GMT"
+   "legend" : {
+      "enabled" : "false"
    },
    "drilldown" : {
       "series" : [
          {
-            "id" : "001",
             "data" : [
                [
                   "Perl",
@@ -23,7 +19,8 @@
                   12
                ]
             ],
-            "name" : "001"
+            "name" : "001",
+            "id" : "001"
          },
          {
             "name" : "002",
@@ -44,7 +41,6 @@
             ]
          },
          {
-            "name" : "003",
             "data" : [
                [
                   "Perl",
@@ -59,10 +55,10 @@
                   9
                ]
             ],
+            "name" : "003",
             "id" : "003"
          },
          {
-            "name" : "004",
             "data" : [
                [
                   "Perl",
@@ -77,10 +73,10 @@
                   10
                ]
             ],
+            "name" : "004",
             "id" : "004"
          },
          {
-            "id" : "005",
             "data" : [
                [
                   "Perl",
@@ -95,10 +91,10 @@
                   12
                ]
             ],
+            "id" : "005",
             "name" : "005"
          },
          {
-            "id" : "006",
             "data" : [
                [
                   "Perl",
@@ -113,9 +109,12 @@
                   7
                ]
             ],
+            "id" : "006",
             "name" : "006"
          },
          {
+            "id" : "007",
+            "name" : "007",
             "data" : [
                [
                   "Perl",
@@ -129,13 +128,9 @@
                   "Blog",
                   10
                ]
-            ],
-            "id" : "007",
-            "name" : "007"
+            ]
          },
          {
-            "name" : "008",
-            "id" : "008",
             "data" : [
                [
                   "Perl",
@@ -149,10 +144,11 @@
                   "Blog",
                   12
                ]
-            ]
+            ],
+            "id" : "008",
+            "name" : "008"
          },
          {
-            "name" : "009",
             "data" : [
                [
                   "Perl",
@@ -167,9 +163,11 @@
                   13
                ]
             ],
+            "name" : "009",
             "id" : "009"
          },
          {
+            "id" : "010",
             "name" : "010",
             "data" : [
                [
@@ -184,8 +182,7 @@
                   "Blog",
                   11
                ]
-            ],
-            "id" : "010"
+            ]
          },
          {
             "data" : [
@@ -224,7 +221,6 @@
             "name" : "012"
          },
          {
-            "name" : "013",
             "data" : [
                [
                   "Perl",
@@ -239,10 +235,10 @@
                   13
                ]
             ],
+            "name" : "013",
             "id" : "013"
          },
          {
-            "name" : "014",
             "data" : [
                [
                   "Perl",
@@ -257,6 +253,7 @@
                   15
                ]
             ],
+            "name" : "014",
             "id" : "014"
          },
          {
@@ -274,12 +271,10 @@
                   15
                ]
             ],
-            "id" : "015",
-            "name" : "015"
+            "name" : "015",
+            "id" : "015"
          },
          {
-            "name" : "016",
-            "id" : "016",
             "data" : [
                [
                   "Perl",
@@ -293,11 +288,11 @@
                   "Blog",
                   13
                ]
-            ]
+            ],
+            "id" : "016",
+            "name" : "016"
          },
          {
-            "name" : "017",
-            "id" : "017",
             "data" : [
                [
                   "Perl",
@@ -311,7 +306,9 @@
                   "Blog",
                   12
                ]
-            ]
+            ],
+            "id" : "017",
+            "name" : "017"
          },
          {
             "data" : [
@@ -328,12 +325,10 @@
                   14
                ]
             ],
-            "id" : "018",
-            "name" : "018"
+            "name" : "018",
+            "id" : "018"
          },
          {
-            "name" : "019",
-            "id" : "019",
             "data" : [
                [
                   "Perl",
@@ -347,10 +342,11 @@
                   "Blog",
                   13
                ]
-            ]
+            ],
+            "name" : "019",
+            "id" : "019"
          },
          {
-            "id" : "020",
             "data" : [
                [
                   "Perl",
@@ -365,9 +361,11 @@
                   13
                ]
             ],
+            "id" : "020",
             "name" : "020"
          },
          {
+            "id" : "021",
             "name" : "021",
             "data" : [
                [
@@ -382,12 +380,11 @@
                   "Blog",
                   10
                ]
-            ],
-            "id" : "021"
+            ]
          },
          {
-            "name" : "022",
             "id" : "022",
+            "name" : "022",
             "data" : [
                [
                   "Perl",
@@ -404,7 +401,6 @@
             ]
          },
          {
-            "name" : "023",
             "data" : [
                [
                   "Perl",
@@ -419,9 +415,11 @@
                   12
                ]
             ],
+            "name" : "023",
             "id" : "023"
          },
          {
+            "name" : "024",
             "id" : "024",
             "data" : [
                [
@@ -436,12 +434,11 @@
                   "Blog",
                   11
                ]
-            ],
-            "name" : "024"
+            ]
          },
          {
-            "name" : "025",
             "id" : "025",
+            "name" : "025",
             "data" : [
                [
                   "Perl",
@@ -458,8 +455,8 @@
             ]
          },
          {
-            "name" : "026",
             "id" : "026",
+            "name" : "026",
             "data" : [
                [
                   "Perl",
@@ -476,8 +473,8 @@
             ]
          },
          {
-            "name" : "027",
             "id" : "027",
+            "name" : "027",
             "data" : [
                [
                   "Perl",
@@ -494,8 +491,8 @@
             ]
          },
          {
-            "name" : "028",
             "id" : "028",
+            "name" : "028",
             "data" : [
                [
                   "Perl",
@@ -512,8 +509,6 @@
             ]
          },
          {
-            "name" : "029",
-            "id" : "029",
             "data" : [
                [
                   "Perl",
@@ -527,9 +522,13 @@
                   "Blog",
                   12
                ]
-            ]
+            ],
+            "id" : "029",
+            "name" : "029"
          },
          {
+            "name" : "030",
+            "id" : "030",
             "data" : [
                [
                   "Perl",
@@ -543,13 +542,9 @@
                   "Blog",
                   10
                ]
-            ],
-            "id" : "030",
-            "name" : "030"
+            ]
          },
          {
-            "name" : "031",
-            "id" : "031",
             "data" : [
                [
                   "Perl",
@@ -563,9 +558,12 @@
                   "Blog",
                   9
                ]
-            ]
+            ],
+            "name" : "031",
+            "id" : "031"
          },
          {
+            "name" : "032",
             "id" : "032",
             "data" : [
                [
@@ -580,8 +578,7 @@
                   "Blog",
                   10
                ]
-            ],
-            "name" : "032"
+            ]
          },
          {
             "name" : "033",
@@ -602,8 +599,6 @@
             ]
          },
          {
-            "name" : "034",
-            "id" : "034",
             "data" : [
                [
                   "Perl",
@@ -617,10 +612,11 @@
                   "Blog",
                   11
                ]
-            ]
+            ],
+            "name" : "034",
+            "id" : "034"
          },
          {
-            "id" : "035",
             "data" : [
                [
                   "Perl",
@@ -635,10 +631,10 @@
                   9
                ]
             ],
-            "name" : "035"
+            "name" : "035",
+            "id" : "035"
          },
          {
-            "name" : "036",
             "data" : [
                [
                   "Perl",
@@ -653,10 +649,10 @@
                   11
                ]
             ],
+            "name" : "036",
             "id" : "036"
          },
          {
-            "name" : "037",
             "data" : [
                [
                   "Perl",
@@ -671,9 +667,11 @@
                   9
                ]
             ],
-            "id" : "037"
+            "id" : "037",
+            "name" : "037"
          },
          {
+            "name" : "038",
             "id" : "038",
             "data" : [
                [
@@ -688,12 +686,9 @@
                   "Blog",
                   12
                ]
-            ],
-            "name" : "038"
+            ]