- Added solution by Ulrich Rieke.

2 files changed, 130 insertions, 0 deletions

diff --git a/challenge-167/ulrich-rieke/cpp/ch-1.cpp b/challenge-167/ulrich-rieke/cpp/ch-1.cpp
new file mode 100644
index 0000000000..92463670fc
--- /dev/null
+++ b/challenge-167/ulrich-rieke/cpp/ch-1.cpp
@@ -0,0 +1,86 @@
+#include <iostream>
+#include <map>
+#include <list>
+#include <algorithm>
+#include <vector>
+#include <cmath>
+
+bool isPrime( int number ) {
+  int stop =  std::sqrt( static_cast<double>( number ) ) ;
+  for ( int i = 2 ; i <= stop ; ++i )
+      if ( number % i == 0 )
+        return false ;
+  return true ;
+}
+
+std::list<int> toList( int n ) {
+  std::list<int> digits ;
+  while ( n != 0 ) {
+      digits.push_back( n % 10 ) ;
+      n /= 10 ;
+  }
+  return digits ;
+}
+//from list to int
+int toInt( const std::list<int> & digits ) {
+  int sum = 0 ;
+  int multiplier = 1 ;
+  for ( auto it = digits.begin( ) ; it != digits.end( ) ; ++it ) {
+      sum += multiplier * *it ;
+      multiplier *= 10 ;
+  }
+  return sum ;
+}
+
+//create cycled digits per performing the rotations on a list of digits
+std::list<int> createCycle( int n ) {
+  std::list<int> cycle ;
+  std::list<int> digits( toList( n ) ) ;
+  cycle.push_back( n ) ;
+  digits.push_back( digits.front( ) ) ;
+  digits.pop_front( ) ;
+  int curnum = toInt( digits ) ;
+  while ( curnum != n ) {
+      cycle.push_back( curnum ) ;
+      digits.push_back( digits.front( ) ) ;
+      digits.pop_front( ) ;
+      curnum = toInt( digits ) ;
+  }
+  return cycle ;
+}
+
+bool isCircularPrime( int n ) {
+  std::list<int> cycle( createCycle( n ) ) ;
+  return std::all_of( cycle.begin( ) , cycle.end( ) , isPrime ) ;
+}
+
+int main( ) {
+  std::vector<int> circularPrimes ;
+  int current = 100 ;
+  std::map<int , int> primesSoFar ;
+  while ( circularPrimes.size( ) != 10 ) {
+      std::list<int> currentDigits( toList( current ) ) ;
+      if ( std::find( currentDigits.begin( ) , currentDigits.end( ) , 0 )
+        == currentDigits.end( ) ) {//we don't want 0's in the number
+    if ( isCircularPrime( current )) {
+        //the following function call may be regarded as wasteful
+        //considering what I did previously ; it's for the sake of
+        //clarity
+        std::list<int> currentCycle = createCycle( current ) ;
+        if ( std::all_of( currentCycle.begin( ) , currentCycle.end( ) ,
+        [&primesSoFar]( int i ) { return primesSoFar.find( i ) ==
+        primesSoFar.end( ) ; } )) {//all cycled numbers not found
+                                        //so far ?
+          circularPrimes.push_back( current ) ;
+          for ( int i : currentCycle )
+          primesSoFar[ i ]++ ;//add them to the numbers found
+        }
+    }
+      }
+      current++ ;
+  }
+  for ( int i : circularPrimes )
+      std::cout << i << ' ' ;
+  std::cout << std::endl ;
+  return 0 ;
+}
diff --git a/challenge-167/ulrich-rieke/perl/ch-1.pl b/challenge-167/ulrich-rieke/perl/ch-1.pl
new file mode 100644
index 0000000000..a198049bd0
--- /dev/null
+++ b/challenge-167/ulrich-rieke/perl/ch-1.pl
@@ -0,0 +1,44 @@
+#!/usr/bin/perl ;
+use strict ;
+use warnings ;
+use feature 'say' ;
+use List::Util qw ( all none ) ;
+use POSIX ;
+
+sub createCycle {
+  my $num = shift ;
+  my @cycle ;
+  push @cycle , $num ;
+  my $rotated = substr( $num , 1 ) . substr( $num , 0 , 1 ) ;
+  while ( $rotated ne $num ) {
+      push @cycle , $rotated ;
+      $rotated = substr( $rotated , 1 ) . substr( $rotated , 0 , 1 ) ;
+  }
+  return @cycle ;
+}
+
+sub isPrime {
+  my $number = shift ;
+  my $stop = sqrt( $number ) ;
+  for my $i ( 2 .. floor( $stop )) {
+      if ( $number % $i == 0 ) {
+        return 0 ;
+      }
+  }
+  return 1 ;
+}
+
+my @circularPrimes ;
+my %circularsSeen ;
+my $current = 100 ;
+while ( scalar( @circularPrimes ) != 10 ) {
+  if ( $current !~ /0/ ) {
+      my @cycle = createCycle( $current ) ;
+      if ( (all { isPrime( $_ ) } @cycle) && (none { $circularsSeen{ $_ } } @cycle )) {
+    push @circularPrimes , $current ;
+    map { $circularsSeen{ $_ }++ } @cycle ;
+      }
+  }
+  $current++ ;
+}
+say join( ', ' , @circularPrimes ) ;