- Added solutions by Ulrich Rieke.

- Added solutions by Dave Jacoby.
- Added solutions by Stephen G Lynn.

1 files changed, 63 insertions, 0 deletions

diff --git a/challenge-249/ulrich-rieke/cpp/ch-2.cpp b/challenge-249/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
index 0000000000..8f52f5dcfb
--- /dev/null
+++ b/challenge-249/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,63 @@
+#include <string>

+#include <iostream>

+#include <algorithm>

+#include <vector>

+#include <numeric>

+

+bool isValid( const std::vector<int> & permu , const std::vector<int> & the_is , 

+      const std::vector<int> & the_ds ) {

+   for ( int i = 0 ; i < the_is.size( ) ; i++ ) {

+      int pos = the_is[ i ] ;

+      if ( permu[pos] >= permu[ pos + 1] ) { 

+	 return false ;

+      }

+   }

+   for ( int i = 0 ; i < the_ds.size( ) ; i++ ) { 

+      int pos = the_ds[ i ] ;

+      if ( permu[pos] <= permu[ pos + 1 ] ) {

+	 return false ;

+      }

+   }

+   return true ;

+}

+

+int main( ) {

+   std::cout << "Please enter a string consisting of capital I and D only!\n" ;

+   std::string line ;

+   std::cin >> line ;

+   std::vector<int> ipositions ;

+   std::vector<int> dpositions ;

+   for ( int i = 0 ; i < line.length( ) ; i++ ) {

+      if ( line.substr( i , 1 ) == "I" ) 

+	 ipositions.push_back( i ) ;

+      else

+	 dpositions.push_back( i ) ;

+   }

+   int len = line.length( ) ;

+   std::vector<int> numbers ( len + 1 ) ;

+   std::iota( numbers.begin( ) , numbers.end( ) , 0 ) ;

+   std::vector<int> result ;

+   if ( dpositions.empty( ) ) {

+      result = numbers ;

+   }

+   else {

+      if ( ipositions.empty( ) ) {

+	 result = numbers ;

+	 std::reverse( result.begin( ) , result.end( ) ) ;

+      }

+      else {

+	 while ( std::next_permutation( numbers.begin( ) , numbers.end( ) ) ) {

+	    if ( isValid( numbers, ipositions, dpositions ) ) { 

+	       result = numbers ;

+	       break ;

+	    }

+         }

+      }

+   }

+   std::cout << "( " ;

+   for ( int i : result ) {

+      std::cout << i << " " ;

+   }

+   std::cout << " )\n" ;

+   return 0 ;

+}