C++/STL Algorithms Merge/inplace merge

Generic merge algorithms: Merge the two sorted halves of vector3 in place to obtain a sorted vector3

<source lang="cpp">

1. include <iostream>
2. include <cassert>
3. include <algorithm>
4. include <vector>

using namespace std; int main() {

 vector<int> vector1(5);
 vector<int> vector2(5);
 vector<int> vector3(10);
 for (int i = 0; i < 5; ++i)
   vector1[i] = 2 * i;
 for (int i = 0; i < 5; ++i)
   vector2[i] = 1 + 2 * i;

 merge(vector1.begin(), vector1.end(), vector2.begin(), vector2.end(), vector3.begin());
 
 inplace_merge(vector3.begin(), vector3.begin() + 5,vector3.end());
 for (int i = 0; i < 10; ++i)
   cout << vector3[i];
 return 0;

} /* 0123456789

*/        
 </source>

inplace_merge a list

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. include <numeric>

/* PRINT_ELEMENTS()

* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/

template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {

   typename T::const_iterator pos;
   std::cout << optcstr;
   for (pos=coll.begin(); pos!=coll.end(); ++pos) {
       std::cout << *pos << " ";
   }
   std::cout << std::endl;

} /* INSERT_ELEMENTS (collection, first, last)

* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/

template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {

   for (int i=first; i<=last; ++i) {
       coll.insert(coll.end(),i);
   }

} using namespace std; int main() {

   list<int> coll;
   // insert two sorted sequences
   INSERT_ELEMENTS(coll,1,7);
   INSERT_ELEMENTS(coll,1,8);
   PRINT_ELEMENTS(coll);
   // find beginning of second part (element after 7)
   list<int>::iterator pos;
   pos = find (coll.begin(), coll.end(),    // range
               7);                          // value
   ++pos;
   // merge into one sorted range
   inplace_merge (coll.begin(), pos, coll.end());
   PRINT_ELEMENTS(coll);

} /* 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8

*/        
 </source>

std::inplace_merge

<source lang="cpp">

1. include <iostream>

using std::cout; using std::endl;

1. include <algorithm>
2. include <vector>
3. include <iterator>

int main() {

  const int SIZE = 10;
  int a1[ SIZE ] = { 1, 3, 5, 7, 9, 1, 3, 5, 7, 9 };
  std::vector< int > v1( a1, a1 + SIZE ); // copy of a
  std::ostream_iterator< int > output( cout, " " );
  cout << "Vector v1 contains: ";
  std::copy( v1.begin(), v1.end(), output );
  std::inplace_merge( v1.begin(), v1.begin() + 2, v1.end() );
  cout << "\nAfter inplace_merge, v1 contains: ";
  std::copy( v1.begin(), v1.end(), output );
  return 0;

} /* Vector v1 contains: 1 3 5 7 9 1 3 5 7 9 After inplace_merge, v1 contains: 1 3 5 7 9 1 3 5 7 9

*/        
 </source>