1 files changed, 69 insertions, 0 deletions
diff --git a/challenge-220/ulrich-rieke/cpp/ch-2.cpp b/challenge-220/ulrich-rieke/cpp/ch-2.cpp
new file mode 100644
index 0000000000..d8dac8ff9f
--- /dev/null
+++ b/challenge-220/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,69 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <cmath>
+
+std::vector<std::string> split( const std::string & startline ,
+      const std::string & sep ) {
+  std::vector<std::string> separated ;
+  std::string::size_type start { 0 } ;
+  std::string::size_type pos ;
+  do {
+      pos = startline.find_first_of( sep , start ) ;
+      separated.push_back( startline.substr(start , pos - start )) ;
+      start = pos + 1 ;
+  } while ( pos != std::string::npos ) ;
+  return separated ;
+}
+
+bool condition( const std::vector<int> & subarray ) {
+  for ( int i = 0 ; i < subarray.size( ) - 1 ; i++ ) {
+      int sum = subarray[ i ] + subarray[ i + 1 ] ;
+      double root = std::sqrt( static_cast<double>(sum) ) ;
+      int rootint = static_cast<int>(std::floor( root ) ) ;
+      if ( rootint * rootint != sum ) {
+    return false ;
+      }
+  }
+  return true ;
+}
+
+int main( ) {
+  std::cout << "Please enter some integers, separated by blanks!\n" ;
+  std::string line ;
+  std::getline( std::cin , line ) ;
+  std::vector<std::string> numberstrings ( split( line , " " ) ) ;
+  std::vector<int> numbers ;
+  for ( auto s : numberstrings ) {
+      numbers.push_back( std::stoi( s ) ) ;
+  }
+  std::sort( numbers.begin( ) , numbers.end( ) ) ;
+  std::vector<std::vector<int>> solution ;
+  if ( condition( numbers ) ) {
+      solution.push_back( numbers ) ;
+  }
+  while ( std::next_permutation( numbers.begin( ) , numbers.end( ) ) ) {
+      if ( condition ( numbers ) ) {
+    solution.push_back( numbers ) ;
+      }
+  }
+  std::cout << "(" ;
+  if ( solution.size( ) == 0 ) {
+      std::cout << "())\n" ;
+  }
+  else {
+      for ( auto seq : solution ) {
+    std::cout << "(" ;
+    for ( int i : seq ) {
+        std::cout << i << " ";
+    }
+    std::cout << ")" ;
+    if ( seq != solution.back( ) ) {
+        std::cout << "," ;
+    }
+      }
+      std::cout << ")\n" ;
+  }
+  return 0 ;
+}