From 388f4e9469ea2003f2cd768f8618f1885320c1e8 Mon Sep 17 00:00:00 2001
From: Paulo Custodio <pauloscustodio@gmail.com>
Date: Fri, 22 Jan 2021 23:55:38 +0000
Subject: Replace Math::Prime::Util by explicit prime number generation

---
 challenge-008/paulo-custodio/perl/ch-1.pl | 28 ++++++++++++++++++++-
 challenge-012/paulo-custodio/perl/ch-1.pl | 27 +++++++++++++++++++-
 challenge-015/paulo-custodio/perl/ch-1.pl | 27 +++++++++++++++++++-
 challenge-076/paulo-custodio/perl/ch-1.pl | 41 +++++++++++++++++++++++++++++--
 4 files changed, 118 insertions(+), 5 deletions(-)

diff --git a/challenge-008/paulo-custodio/perl/ch-1.pl b/challenge-008/paulo-custodio/perl/ch-1.pl
index cde823ccf9..9fbbe09470 100644
--- a/challenge-008/paulo-custodio/perl/ch-1.pl
+++ b/challenge-008/paulo-custodio/perl/ch-1.pl
@@ -11,7 +11,32 @@
 use strict;
 use warnings;
 use 5.030;
-use Math::Prime::Util 'next_prime', 'is_prime';
+
+# check if number is prime
+sub is_prime {
+	my($n) = @_;
+
+    return 0 if $n <= 1;
+    return 1 if $n <= 3;
+    
+    return 0 if ($n % 2)==0 || ($n % 3)==0;
+    
+    for (my $i = 5; $i*$i <= $n; $i += 6) {
+		return 0 if ($n % $i)==0 || ($n % ($i+2))==0;
+	}
+    
+    return 1;
+}
+
+# next prime
+sub next_prime {
+	my($n) = @_;
+	
+	return 2 if $n <= 1;
+	my $p = $n;
+	1 while !is_prime(++$p);
+	return $p;
+}
 
 # Euclid proved that 2^(p−1)*(2^p − 1) is an even perfect number 
 # whenever 2p − 1 is prime 
@@ -27,6 +52,7 @@ sub perfect_iter {
 }
 
 
+# main
 my $n = shift || 5;
 my $iter = perfect_iter();
 for (1..$n) {
diff --git a/challenge-012/paulo-custodio/perl/ch-1.pl b/challenge-012/paulo-custodio/perl/ch-1.pl
index 0bd11f659d..411ed1e154 100644
--- a/challenge-012/paulo-custodio/perl/ch-1.pl
+++ b/challenge-012/paulo-custodio/perl/ch-1.pl
@@ -11,7 +11,32 @@
 use strict;
 use warnings;
 use 5.030;
-use Math::Prime::Util 'next_prime', 'is_prime';
+
+# check if number is prime
+sub is_prime {
+	my($n) = @_;
+
+    return 0 if $n <= 1;
+    return 1 if $n <= 3;
+    
+    return 0 if ($n % 2)==0 || ($n % 3)==0;
+    
+    for (my $i = 5; $i*$i <= $n; $i += 6) {
+		return 0 if ($n % $i)==0 || ($n % ($i+2))==0;
+	}
+    
+    return 1;
+}
+
+# next prime
+sub next_prime {
+	my($n) = @_;
+	
+	return 2 if $n <= 1;
+	my $p = $n;
+	1 while !is_prime(++$p);
+	return $p;
+}
 
 sub euclid_iter {
 	my $prime = 1;
diff --git a/challenge-015/paulo-custodio/perl/ch-1.pl b/challenge-015/paulo-custodio/perl/ch-1.pl
index 655124d8bb..59e37ef0d0 100644
--- a/challenge-015/paulo-custodio/perl/ch-1.pl
+++ b/challenge-015/paulo-custodio/perl/ch-1.pl
@@ -19,7 +19,32 @@
 use strict;
 use warnings;
 use 5.030;
-use Math::Prime::Util 'next_prime';
+
+# check if number is prime
+sub is_prime {
+	my($n) = @_;
+
+    return 0 if $n <= 1;
+    return 1 if $n <= 3;
+    
+    return 0 if ($n % 2)==0 || ($n % 3)==0;
+    
+    for (my $i = 5; $i*$i <= $n; $i += 6) {
+		return 0 if ($n % $i)==0 || ($n % ($i+2))==0;
+	}
+    
+    return 1;
+}
+
+# next prime
+sub next_prime {
+	my($n) = @_;
+	
+	return 2 if $n <= 1;
+	my $p = $n;
+	1 while !is_prime(++$p);
+	return $p;
+}
 
 sub prime_iter {
 	my($strong) = @_;
diff --git a/challenge-076/paulo-custodio/perl/ch-1.pl b/challenge-076/paulo-custodio/perl/ch-1.pl
index 99a25bb519..5619acd725 100644
--- a/challenge-076/paulo-custodio/perl/ch-1.pl
+++ b/challenge-076/paulo-custodio/perl/ch-1.pl
@@ -22,7 +22,6 @@ use warnings;
 use 5.030;
 use Math::Combinatorics;
 use List::Util 'sum';
-use Math::Prime::Util 'primes';
 
 my($N) = shift;
 
@@ -35,13 +34,51 @@ else {
 }
 
 
+# check if number is prime
+sub is_prime {
+	my($n) = @_;
+
+    return 0 if $n <= 1;
+    return 1 if $n <= 3;
+    
+    return 0 if ($n % 2)==0 || ($n % 3)==0;
+    
+    for (my $i = 5; $i*$i <= $n; $i += 6) {
+		return 0 if ($n % $i)==0 || ($n % ($i+2))==0;
+	}
+    
+    return 1;
+}
+
+# next prime
+sub next_prime {
+	my($n) = @_;
+	
+	return 2 if $n <= 1;
+	my $p = $n;
+	1 while !is_prime(++$p);
+	return $p;
+}
+
+# get all primes up to N
+sub primes {
+	my($n) = @_;
+	my $p = 2;
+	my @primes;
+	while ($p <= $n) {
+		push @primes, $p;
+		$p = next_prime($p);
+	}
+	return @primes;
+}
+
 # check all combinations for the shortest that adds up to N
 sub find_set {
 	my($n) = @_;
 
 	# get all primes up to N, 1 not included; 
 	# append primes 2 and 3 to be able to solve special cases 4 and 6
-	my @primes = (@{primes($n)}, 2, 3);
+	my @primes = (primes($n), 2, 3);
 
 	my @solution;
 	for my $k (1 .. scalar(@primes)) {
-- 
cgit