Merge pull request #3387 from gnustavo/097

Add Gustavo Chaves's solutions to challenge 097

2 files changed, 57 insertions, 0 deletions

diff --git a/challenge-097/gustavo-chaves/perl/ch-1.pl b/challenge-097/gustavo-chaves/perl/ch-1.pl
new file mode 100755
index 0000000000..11a2d2f608
--- /dev/null
+++ b/challenge-097/gustavo-chaves/perl/ch-1.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-097/
+# TASK #1 › Caesar Cipher
+
+use 5.030;
+use warnings;
+
+my ($N, $S) = @ARGV;
+
+# ($N, $S) = (3, "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG");
+
+my $alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+my $caesar = substr($alphabet, -$N) . substr($alphabet, 0, length($alphabet) - $N);
+
+$alphabet .= lc $alphabet;
+$caesar .= lc $caesar;
+
+for ($S) {
+    say eval "tr/$alphabet/$caesar/r";
+}
diff --git a/challenge-097/gustavo-chaves/perl/ch-2.pl b/challenge-097/gustavo-chaves/perl/ch-2.pl
new file mode 100755
index 0000000000..bad7ffa917
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+++ b/challenge-097/gustavo-chaves/perl/ch-2.pl
@@ -0,0 +1,36 @@
+#!/usr/bin/env perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-097/
+# TASK #2 › Binary Substrings
+
+use 5.030;
+use warnings;
+use List::AllUtils qw(sum0 pairwise reduce);
+
+my ($B, $S) = @ARGV;
+
+# ($B, $S) = qw(101100101 3);
+# ($B, $S) = qw(10110111 4);
+
+length($B) % $S == 0
+    or die "The length of the string '$B' must be a multiple of $S\n";
+
+my @substrings = $B =~ /(.{$S})/g;
+
+my (@distance, @flips);
+
+# Calculate the distances between each pair of substrings and the total number
+# of flips to change all of them to be equal to each one.
+for my $i (0 .. $#substrings) {
+    my @from = split //, $substrings[$i];
+    for my $j (0 .. $#substrings) {
+        my @to = split //, $substrings[$j];
+        $distance[$i][$j] = sum0 pairwise {$a != $b} @from, @to;
+    }
+    $flips[$i] = sum0 @{$distance[$i]};
+}
+
+# Find the index of the substring which requires the minimum number of flips.
+my $i = reduce {$flips[$a] < $flips[$b] ? $a : $b} 0 .. $#flips;
+
+say "$flips[$i] to make all substrings equal to '$substrings[$i]' ($i)";