Merge pull request #9291 from wlmb/challenges

Solve PWC249

3 files changed, 35 insertions, 0 deletions

diff --git a/challenge-249/wlmb/blog.txt b/challenge-249/wlmb/blog.txt
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+++ b/challenge-249/wlmb/blog.txt
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+https://wlmb.github.io/2023/12/25/PWC249/
diff --git a/challenge-249/wlmb/perl/ch-1.pl b/challenge-249/wlmb/perl/ch-1.pl
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+++ b/challenge-249/wlmb/perl/ch-1.pl
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+#!/usr/bin/env perl
+# Perl weekly challenge 249
+# Task 1:  Equal Pairs
+#
+# See https://wlmb.github.io/2023/12/25/PWC249/#task-1-equal-pairs
+use v5.36;
+use List::Util qw(all);
+die <<~"FIN" unless @ARGV;
+    Usage: $0 N1 [N2...]
+    to find pairs of equal numbers N_i == N_j
+    FIN
+my %count;
+$count{$_}++ for @ARGV;
+say "(@ARGV) => ",
+    (all {$_%2==0} values %count)
+    ? map {("($_ $_) ") x ($count{$_}/2)} sort {$a<=>$b} keys %count:"()"
diff --git a/challenge-249/wlmb/perl/ch-2.pl b/challenge-249/wlmb/perl/ch-2.pl
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+++ b/challenge-249/wlmb/perl/ch-2.pl
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+#!/usr/bin/env perl
+# Perl weekly challenge 249
+# Task 2:  DI String Match
+#
+# See https://wlmb.github.io/2023/12/25/PWC249/#task-2-di-string-match
+use v5.36;
+die <<~"FIN" unless @ARGV;
+    Usage: $0 S1 [S2...]
+    where S_i is a string of D's and I's, to produce a permutation of
+    indices 0..length of S_i that increases or decreases according to
+    the letters D or I.
+    FIN
+for(@ARGV){
+    my @output;
+    push @output,my $max=my $min=0;
+    push @output, ($_ eq "D")?++$max:--$min for reverse split "";
+    say "$_ => (",join(",", reverse map {$_-$min} @output), ")"
+}