- Added solution by Ulrich Rieke.

2 files changed, 53 insertions, 0 deletions

diff --git a/challenge-167/ulrich-rieke/haskell/ch-1.hs b/challenge-167/ulrich-rieke/haskell/ch-1.hs
new file mode 100644
index 0000000000..b54ca89ec9
--- /dev/null
+++ b/challenge-167/ulrich-rieke/haskell/ch-1.hs
@@ -0,0 +1,26 @@
+module Challenge167
+  where
+
+isPrime :: Int -> Bool
+isPrime n
+  |n == 2 = True
+  |n == 1 = False
+  |otherwise = null $ filter (\i -> mod n i == 0 ) [2 .. root]
+  where
+      root :: Int
+      root = floor $ sqrt $ fromIntegral n
+
+findCycle :: Int -> [Int]
+findCycle n = (takeWhile (/= n ) $ iterate step ( step n )) ++ [n]
+where
+  step :: Int -> Int
+  step d = read ( tail s ++ [head s] )
+  where
+    s = show d
+
+solution :: [Int]
+solution = take 10 $ filter (\i -> (noNull i ) && ( all (\d -> isPrime d
+&& d >= i ) $ findCycle i )) [100 , 101 ..]
+  where
+  noNull :: Int -> Bool
+  noNull d = not  ( elem '0' $ show d )
diff --git a/challenge-167/ulrich-rieke/raku/ch-1.raku b/challenge-167/ulrich-rieke/raku/ch-1.raku
new file mode 100644
index 0000000000..607adff4f5
--- /dev/null
+++ b/challenge-167/ulrich-rieke/raku/ch-1.raku
@@ -0,0 +1,27 @@
+use v6 ;
+
+sub findCycles( Int $n is copy ) {
+  my $numberstring = ~$n ;
+  my @cycle ;
+  my $rotated = $numberstring.substr( 1 ) ~ $numberstring.substr( 0 , 1 ) ;
+  @cycle.push( +$rotated ) ;
+  while ( $rotated ne $numberstring ) {
+      $rotated = $rotated.substr( 1 ) ~ $rotated.substr(0 , 1 ) ;
+      @cycle.push( +$rotated ) ;
+  }
+  return @cycle ;
+}
+
+my @circularPrimes ;
+my $current = 100 ;
+while ( @circularPrimes.elems != 10 ) {
+  if ( ~$current !~~ /0/ ) {
+      my @cycle = findCycles( $current ) ;
+      my @selected = grep ( { $_ >= $current } ) , @cycle ;
+      if ( (so is-prime @cycle.all) && (@selected.elems == @cycle.elems) ) {
+    @circularPrimes.push( $current ) ;
+      }
+  }
+  $current++ ;
+}
+say @circularPrimes.join( ', ' ) ;