1 files changed, 55 insertions, 0 deletions
diff --git a/challenge-249/ulrich-rieke/cpp/ch-1.cpp b/challenge-249/ulrich-rieke/cpp/ch-1.cpp
new file mode 100755
index 0000000000..49d2e3d9e3
--- /dev/null
+++ b/challenge-249/ulrich-rieke/cpp/ch-1.cpp
@@ -0,0 +1,55 @@
+#include <vector>
+#include <string>
+#include <iostream>
+#include <algorithm>
+#include <utility>
+#include <map>
+
+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 ;
+}
+
+int main( ) {
+   std::cout << "Enter an even number of integers, separated by blanks!\n" ;
+   std::string line ;
+   std::getline( std::cin , line ) ;
+   std::vector<int> numbers ;
+   std::vector<std::string> numberstrings { split( line , " " ) } ;
+   for ( auto s : numberstrings ) 
+      numbers.push_back( std::stoi( s ) ) ;
+   std::map<int , int> frequencies ;
+   for ( auto it = numbers.begin( ) ; it != numbers.end( ) ; ++it ) {
+      frequencies[*it]++ ;
+   }
+   if ( std::all_of( frequencies.begin( ) , frequencies.end( ) , []( const 
+	       auto & p ) { return p.second % 2 == 0 ; } ) ) {
+      std::sort( numbers.begin( ) , numbers.end( ) ) ;
+      std::vector<std::pair<int , int>> result ;
+      int pos = 0 ;
+      int len = numbers.size( ) ;
+      while ( pos <= len - 2 ) {
+	 std::pair<int, int> current { std::make_pair( numbers[ pos ] , 
+	       numbers[ pos + 1 ] ) } ;
+	 result.push_back( current ) ;
+	 pos += 2 ;
+      }
+      std::cout << "(" ;
+      for ( auto p : result ) {
+	 std::cout << "[" << p.first << ',' << p.second << "]" ;
+      }
+      std::cout << ")\n" ;
+   }
+   else {
+      std::cout << "()\n" ;
+   }
+   return 0 ;
+}