From dee6d2782db5c9d5bbab1bbb8d2bd9ff9f6fd34a Mon Sep 17 00:00:00 2001
From: Mohammad S Anwar <mohammad.anwar@yahoo.com>
Date: Wed, 27 Dec 2023 11:07:16 +0000
Subject: - Added solutions by Ulrich Rieke. - Added solutions by Dave Jacoby.
 - Added solutions by Stephen G Lynn.

---
 challenge-249/ulrich-rieke/cpp/ch-1.cpp | 55 ++++++++++++++++++++++++++++
 challenge-249/ulrich-rieke/cpp/ch-2.cpp | 63 +++++++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100755 challenge-249/ulrich-rieke/cpp/ch-1.cpp
 create mode 100755 challenge-249/ulrich-rieke/cpp/ch-2.cpp

(limited to 'challenge-249/ulrich-rieke/cpp')

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 ;
+}
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 ;
+}
-- 
cgit