From 615f7aa7e2613c9daea36b8456c4771a98399b90 Mon Sep 17 00:00:00 2001
From: Flavio Poletti <flavio@polettix.it>
Date: Tue, 5 Oct 2021 19:23:05 +0200
Subject: Add polettix's solution to challenge-133

---
 challenge-133/polettix/blog.txt       |  1 +
 challenge-133/polettix/blog1.txt      |  1 +
 challenge-133/polettix/perl/ch-1.pl   | 13 +++++++++++++
 challenge-133/polettix/perl/ch-2.pl   | 33 +++++++++++++++++++++++++++++++++
 challenge-133/polettix/raku/ch-1.raku | 10 ++++++++++
 challenge-133/polettix/raku/ch-2.raku | 28 ++++++++++++++++++++++++++++
 6 files changed, 86 insertions(+)
 create mode 100644 challenge-133/polettix/blog.txt
 create mode 100644 challenge-133/polettix/blog1.txt
 create mode 100644 challenge-133/polettix/perl/ch-1.pl
 create mode 100644 challenge-133/polettix/perl/ch-2.pl
 create mode 100644 challenge-133/polettix/raku/ch-1.raku
 create mode 100644 challenge-133/polettix/raku/ch-2.raku

diff --git a/challenge-133/polettix/blog.txt b/challenge-133/polettix/blog.txt
new file mode 100644
index 0000000000..7c61e5cf32
--- /dev/null
+++ b/challenge-133/polettix/blog.txt
@@ -0,0 +1 @@
+https://github.polettix.it/ETOOBUSY/2021/10/06/pwc133-integer-square-root/
diff --git a/challenge-133/polettix/blog1.txt b/challenge-133/polettix/blog1.txt
new file mode 100644
index 0000000000..2df1e12cfe
--- /dev/null
+++ b/challenge-133/polettix/blog1.txt
@@ -0,0 +1 @@
+https://github.polettix.it/ETOOBUSY/2021/10/07/pwc133-smith-numbers/
diff --git a/challenge-133/polettix/perl/ch-1.pl b/challenge-133/polettix/perl/ch-1.pl
new file mode 100644
index 0000000000..8f20ddef96
--- /dev/null
+++ b/challenge-133/polettix/perl/ch-1.pl
@@ -0,0 +1,13 @@
+#!/usr/bin/env perl
+use v5.24;
+use warnings;
+use experimental 'signatures';
+no warnings 'experimental::signatures';
+sub integer_square_root ($n) {
+   return $n if $n < 2;
+   my $x = $n >> 1;  # first estimate
+   my $y = $x + 1;   # just to get started with $x < $y
+   ($x, $y) = (($x + int($n / $x)) >> 1, $x) while $x < $y;
+   return $y;
+}
+say integer_square_root(shift // die "$0 <n>\n");
diff --git a/challenge-133/polettix/perl/ch-2.pl b/challenge-133/polettix/perl/ch-2.pl
new file mode 100644
index 0000000000..23327d1aa6
--- /dev/null
+++ b/challenge-133/polettix/perl/ch-2.pl
@@ -0,0 +1,33 @@
+#!/usr/bin/env perl
+use v5.24;
+use warnings;
+use experimental 'signatures';
+no warnings 'experimental::signatures';
+use List::Util 'sum';
+sub is_smith ($x) {
+   my $sum = sum split m{}mxs, $x;
+   my $div = 2;
+   my $ndiv = 0;
+   while ($x > 1 && $sum > -1) {
+      if ($x % $div == 0) {
+         my $subsum = sum split m{}mxs, $div;
+         while ($x % $div == 0) {
+            $sum -= $subsum;
+            $x /= $div;
+            ++$ndiv;
+         }
+      }
+      $div = $div % 2 ? $div + 2 : 3;
+   }
+   return $sum == 0 && $ndiv > 1;
+}
+sub smith_first ($n) {
+   my @retval;
+   my $candidate = 3; # one less of first composite number
+   while ($n > @retval) {
+      next unless is_smith(++$candidate);
+      push @retval, $candidate;
+   }
+   return @retval;
+}
+say for smith_first(shift // 10);
diff --git a/challenge-133/polettix/raku/ch-1.raku b/challenge-133/polettix/raku/ch-1.raku
new file mode 100644
index 0000000000..0db13b24d8
--- /dev/null
+++ b/challenge-133/polettix/raku/ch-1.raku
@@ -0,0 +1,10 @@
+#!/usr/bin/env raku
+use v6;
+sub integer-square-root (Int:D $n where * >= 0) {
+   return $n if $n < 2;
+   my $x = $n +> 1;  # first estimate
+   my $y = $x + 1;   # just to get started with $x < $y
+   ($x, $y) = (($x + ($n / $x).Int) +> 1, $x) while $x < $y;
+   return $y;
+}
+sub MAIN (Int:D $n where * >= 0) { put integer-square-root($n) }
diff --git a/challenge-133/polettix/raku/ch-2.raku b/challenge-133/polettix/raku/ch-2.raku
new file mode 100644
index 0000000000..bc0639034d
--- /dev/null
+++ b/challenge-133/polettix/raku/ch-2.raku
@@ -0,0 +1,28 @@
+#!/usr/bin/env raku
+use v6;
+sub is-smith (Int:D() $x is copy where * > 0) {
+   my $sum = $x.comb(/\d/).sum;
+   my $div = 2;
+   my $ndiv = 0;
+   while $x > 1 && $sum > -1 {
+      if $x %% $div {
+         my $subsum = $div.comb(/\d/).sum;
+         while $x %% $div {
+            $sum -= $subsum;
+            $x /= $div;
+            ++$ndiv;
+         }
+      }
+      $div += $div == 2 ?? 1 !! 2;
+   }
+   return $sum == 0 && $ndiv > 1;
+}
+sub smith-first (Int:D $n is copy where * > 0) {
+   my $candidate = 3; # one less of first composite number
+   gather while $n > 0 {
+      next unless is-smith(++$candidate);
+      take $candidate;
+      --$n;
+   }
+}
+sub MAIN ($n = 10) { .put for smith-first($n) }
-- 
cgit