Add Gustavo Chaves's solutions to challenge 102

2 files changed, 50 insertions, 0 deletions

diff --git a/challenge-102/gustavo-chaves/perl/ch-1.pl b/challenge-102/gustavo-chaves/perl/ch-1.pl
new file mode 100755
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+++ b/challenge-102/gustavo-chaves/perl/ch-1.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/env perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-102/
+# TASK #1 › Rare Numbers
+
+use 5.030;
+use warnings;
+
+my $digits = shift or die "Usage: $0 N\n";
+
+my @squares = (0);
+while ($squares[-1] < 2*(10**$digits)) {
+    push @squares, @squares * @squares;
+}
+
+# This is very inefficient... :-(
+
+for (my $r = $#squares; $r > 1; --$r) {
+    my $xx = $squares[$r];
+    for (my $l = $r-1; $l >= 1; --$l) {
+        my $yy = $squares[$l];
+        my $dr = $xx + $yy;
+        next unless ($dr % 2) == 0;
+        my $dl = $xx - $yy;
+        next unless ($dl % 2) == 0;
+        my $R = $dr / 2;
+        next unless length("$R") == $digits;
+        my $L = sprintf "%0${digits}d", $dl / 2;
+        say $R if "$R" eq reverse("$L");
+    }
+}
diff --git a/challenge-102/gustavo-chaves/perl/ch-2.pl b/challenge-102/gustavo-chaves/perl/ch-2.pl
new file mode 100755
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+++ b/challenge-102/gustavo-chaves/perl/ch-2.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-102/
+# TASK #2 › Hash-counting String
+
+use 5.030;
+use warnings;
+
+my $N = shift or die "Usage: $0 N\n";
+
+my $string = '#';
+
+while ($N > 1) {
+    $string = "$N$string";
+    $N -= 1 + length "$N";
+    $string = "#$string" if $N > 0;
+}
+
+say $string;