- Added solutions by Ulrich Rieke.

1 files changed, 45 insertions, 0 deletions

diff --git a/challenge-156/ulrich-rieke/cpp/ch-1.cpp b/challenge-156/ulrich-rieke/cpp/ch-1.cpp
new file mode 100644
index 0000000000..abcbd0512b
--- /dev/null
+++ b/challenge-156/ulrich-rieke/cpp/ch-1.cpp
@@ -0,0 +1,45 @@
+#include <vector>
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+
+bool isPrime( int n ) {
+  if ( n == 1 )
+      return false ;
+  if ( n == 2 )
+      return true ;
+  int root = static_cast<int>( floor( sqrt( static_cast<double>( n ) ))) ;
+  for ( int i = 2 ; i < root + 1 ; i++ )
+      if ( n % i == 0 )
+        return false ;
+  return true ;
+}
+
+std::vector<int> toBinary( int n ) {
+  std::vector<int> binaryDigits ;
+  while ( n != 0 ) {
+      binaryDigits.push_back( n % 2 ) ;
+      n /= 2 ;
+  }
+  return binaryDigits ;
+}
+
+bool isPernicious( int n ) {
+  std::vector<int> binaryDigits { toBinary( n ) } ;
+  return isPrime( std::count( binaryDigits.begin( ) , binaryDigits.end( ) ,
+        1 )) ;
+}
+
+int main( ) {
+  std::vector<int> perniciousNumbers ;
+  int current = 0 ;
+  while ( perniciousNumbers.size( ) != 10 ) {
+      current++ ;
+      if ( isPernicious( current ) )
+    perniciousNumbers.push_back( current ) ;
+  }
+  for ( int i : perniciousNumbers )
+      std::cout << i << ' ' ;
+  std::cout << std::endl ;
+  return 0 ;
+}