- Added solutions by Laurent Rosenfeld.

6 files changed, 102 insertions, 0 deletions

diff --git a/challenge-154/laurent-rosenfeld/blog.txt b/challenge-154/laurent-rosenfeld/blog.txt
new file mode 100644
index 0000000000..c567d36e2e
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/blog.txt
@@ -0,0 +1 @@
+http://blogs.perl.org/users/laurent_r/2022/03/perl-weekly-challenge-154-missing-permutations-and-padovan-primes.html
diff --git a/challenge-154/laurent-rosenfeld/perl/ch-1.pl b/challenge-154/laurent-rosenfeld/perl/ch-1.pl
new file mode 100644
index 0000000000..83f1f441d4
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/perl/ch-1.pl
@@ -0,0 +1,23 @@
+use strict;
+use warnings;
+use feature "say";
+
+my @permutations;
+my %given_perm = map { $_ => 1 } qw/
+    PELR PREL PERL PRLE PLER PLRE EPRL EPLR ERPL
+    ERLP ELPR ELRP RPEL RPLE REPL RELP RLPE RLEP
+    LPER LPRE LEPR LRPE LREP /;
+
+sub permute {
+    my ($str, @vals) = @_;
+    if (scalar @vals == 0) {
+        push @permutations, $str;
+        return;
+    }
+    permute("$str" . $vals[$_], @vals[0..$_-1],
+        @vals[$_+1..$#vals]) for 0..$#vals;
+}
+permute "", split //, (keys %given_perm)[0];
+for my $perm (@permutations) {
+    say "$perm is missing" unless exists $given_perm{$perm};
+}
diff --git a/challenge-154/laurent-rosenfeld/perl/ch-2.pl b/challenge-154/laurent-rosenfeld/perl/ch-2.pl
new file mode 100644
index 0000000000..4261ec9dc6
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/perl/ch-2.pl
@@ -0,0 +1,50 @@
+use strict;
+use warnings;
+use feature "say";
+use constant MAX => 10000; # MAX must be an even number
+
+my @primes = prime_list(MAX);
+# say "@primes"; # 2 3 5 7 11 13 17 19 23 29 31 37 41 ...
+
+my @padovans = (1, 1, 1);
+for my $i (3..140) {
+    $padovans[$i] = $padovans[$i-2] + $padovans[$i-3]
+}
+# say "@padovans"; # 1 1 1 2 2 3 4 5 7 9 12 16 21 28 37 ...
+
+my $count = 0;
+my $last_pad = 0;
+for my $pad (@padovans) {
+    next if $pad == $last_pad;
+    $last_pad = $pad;
+    next unless is_prime($pad);
+    say $pad;
+    $count++;
+    last if $count > 9;
+}
+
+sub prime_list {
+    my $max = shift;
+    my @prime_list = (2, 3, 5);
+    PRIMES: for my $c (7..$max) {
+            for my $i (2..$c/2) {
+                next PRIMES unless $c % $i;
+            }
+            push @prime_list, $c;
+    }
+    return @prime_list;
+}
+sub is_prime {
+    my $num = shift;
+    for my $prime (@primes) {
+        return 1 if $num == $prime;
+        return 0 if $prime > $num;
+        return 0 unless $num % $prime;
+    }
+    my $test = MAX+1;
+    while ($test < int(sqrt($num))) {
+        return 0 unless $num % $test;
+        $test += 2;
+    }
+    return 1;
+}
diff --git a/challenge-154/laurent-rosenfeld/raku/ch-1.raku b/challenge-154/laurent-rosenfeld/raku/ch-1.raku
new file mode 100644
index 0000000000..f378f0da4f
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/raku/ch-1.raku
@@ -0,0 +1,7 @@
+my $given_perm = set(qw/
+    PELR PREL PERL PRLE PLER PLRE EPRL EPLR ERPL
+    ERLP ELPR ELRP RPEL RPLE REPL RELP RLPE RLEP
+    LPER LPRE LEPR LRPE LREP /);
+for "PERL".comb.permutations>>.join("") -> $perm {
+    say "$perm is missing" if $perm ∉ $given_perm;
+}
diff --git a/challenge-154/laurent-rosenfeld/raku/ch-1a.raku b/challenge-154/laurent-rosenfeld/raku/ch-1a.raku
new file mode 100644
index 0000000000..6d1e50df30
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/raku/ch-1a.raku
@@ -0,0 +1,6 @@
+my $given_perm = set(qw/
+    PELR PREL PERL EPRL EPLR ERPL
+    ERLP ELPR ELRP RPEL RLPE RLEP
+    LPER LPRE LEPR LRPE LREP /);
+my $perms = set($given_perm.keys[0].comb.permutations>>.join(""));
+say "Missing: ", ~($perms (-) $given_perm);
diff --git a/challenge-154/laurent-rosenfeld/raku/ch-2.raku b/challenge-154/laurent-rosenfeld/raku/ch-2.raku
new file mode 100644
index 0000000000..9ddb631bdf
--- /dev/null
+++ b/challenge-154/laurent-rosenfeld/raku/ch-2.raku
@@ -0,0 +1,15 @@
+my @padovans = 1, 1, 1, -> $a, $b, $c { $a + $b } ... *;
+# say @padovans[0..10];  # (1 1 1 2 2 3 4 5 7 9 12)
+my $max = 10;
+my $prev_pad = 1;
+for @padovans -> $pad {
+    next if $prev_pad == $pad;
+    if $pad.is-prime {
+        print "$pad ";
+        $max--;
+    }
+    $prev_pad = $pad;
+    last if $max <= 0;
+}
+say "";
+say now - INIT now;