C++ Tutorial/STL Algorithms Merge/inplace merge

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

#include <iostream>
#include <cassert>
#include <algorithm>
#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

inplace_merge a list

/* 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.
 */
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#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

inplace_merge, reverse_copy, and unique_copy.

#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
using namespace std;
int main()
{
   const int SIZE = 10;
   int a1[ SIZE ] = { 1, 3, 5, 7, 9, 1, 3, 5, 7, 9 };
   vector< int > v1( a1, a1 + SIZE );
   inplace_merge( v1.begin(), v1.begin() + 5, v1.end() );
   
   vector< int > results1;
   unique_copy( v1.begin(), v1.end(), back_inserter( results1 ) );
   
   vector< int > results2;
   reverse_copy( v1.begin(), v1.end(), back_inserter( results2 ) );
   cout << endl;
   return 0;
}

std::inplace_merge

#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <vector>
#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