[euler] problem 60

categories/euler/prob060-andreoss.pl

@@ -0,0 +1,68 @@
+use v6;
+
+=begin pod
+
+=TITLE Prime pair sets 
+
+=AUTHOR Andrei Osipov
+
+The primes 3, 7, 109, and 673, are quite remarkable. By taking any two
+primes and concatenating them in any order the result will always be
+prime. For example, taking 7 and 109, both 7109 and 1097 are
+prime. The sum of these four primes, 792, represents the lowest sum
+for a set of four primes with this property.
+
+Find the lowest sum for a set of five primes for which any two primes
+concatenate to produce another prime.
+
+=end   pod
+
+subset Prime of Int where *.is-prime;
+
+
+sub infix:«R»($a, $b) {
+    +( $a ~ $b ) & +( $b ~ $a ) ~~ Prime 
+}
+
+multi are-remarkable()          { True }
+multi are-remarkable($a)        { True }
+multi are-remarkable($a, *@xs)  {
+    $a R @xs.all
+}
+
+sub get-remarkable(  :@primes   is copy
+                   , *@sequence
+                  ) {
+    gather while my $x = @primes.shift {
+        if are-remarkable $x, @sequence {
+            take(|@sequence , $x) if @sequence;
+            take $_
+                for get-remarkable
+                     :@primes
+                    , @sequence, $x
+        }
+    }
+}
+
+sub MAIN(  Int  :$limit   = 10_000
+         , Bool :$verbose = False
+         , Int  :$size    = 5
+        ) {
+
+    my @primes = grep Prime , 1 .. $limit;
+
+    for get-remarkable :@primes -> @r {
+
+        say @r.perl if $verbose ;
+
+        if @r == $size {
+            $verbose
+                ?? say "The sequence is @r[], the sum is {[+] @r}"
+                !! say [+] @r
+            and last
+        }
+    }
+
+    say "Done in {now - BEGIN now}." if $verbose;
+}
+

categories/euler/prob066-andreoss.pl

@@ -34,7 +34,7 @@
 Find the value of D ≤ 1000 in minimal solutions of x for which the largest
 value of x is obtained.
 
-The following algoritm was used for the solution:
+The following algorithm was used for the solution:
 L<https://en.wikipedia.org/wiki/Chakravala_method>
 
 =end pod

categories/euler/prob080-andreoss.pl

@@ -18,7 +18,7 @@
 sums of the first one hundred decimal digits for all the irrational square
 roots.
 
-The following algoritm was used for the solution:
+The following algorithm was used for the solution:
 L<http://www.afjarvis.staff.shef.ac.uk/maths/jarvisspec02.pdf>
 
 =end pod

t/categories/euler.t

@@ -456,6 +456,17 @@ subtest {
     check-example-solutions($problem, $expected-output, @authors)
 }, "prob059";
 
+subtest {
+    plan 1;
+
+    my $problem = "prob060";
+    my @authors = <andreoss>;
+    my $expected-output = 26033;
+
+    check-example-solutions($problem, $expected-output, @authors)
+}, "prob060";
+
+
 subtest {
     plan 2;