C++ Tutorial/STL Algorithms Helper/next permutation

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All permutations of ABC by use of next_permutation()

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
  vector<char> v;
  unsigned i;
  for(i=0; i<3; i++) 
    v.push_back("A"+i);
  do {
    for(i=0; i < v.size(); i++){
      cout << v[i] << endl;
    }
  } while(next_permutation(v.begin(), v.end()));
  return 0;
}

All permutations of ABC by use of prev_permutation()

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
  vector<char> v;
  unsigned i;
  for(i=0; i<3; i++) v.push_back("A"+i);
  prev_permutation(v.begin(), v.end());
  
  do {
    for(i=0; i<v.size(); i++)
      cout << v[i] << endl;
  } while(prev_permutation(v.begin(), v.end()));
  return 0;
}

Illustrating the generic next_permutation algorithms

#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
  vector<int> vector1(3);
  for (int i = 0; i < 3; ++i) 
     vector1[i] = i;
  // In lexicographical order the permutations of 0 1 2 are
  // 0 1 2, 0 2 1, 1 0 2, 1 2 0, 2 0 1, 2 1 0. 
  // Show that from 0 1 2 next_permutation produces 0 2 1:
  next_permutation(vector1.begin(), vector1.end());
  cout << vector1[0] << " ";
  cout << vector1[1] << " ";
  cout << vector1[2] << " ";
  return 0;
}
0 2 1

next_permutation() and prev_permutation().

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
  vector<char> v;
  unsigned i;
  for(i=0; i<3; i++) 
    v.push_back("A"+i);
  do {
    for(i=0; i < v.size(); i++){
      cout << v[i] << endl;
    }
  } while(next_permutation(v.begin(), v.end()));
  prev_permutation(v.begin(), v.end());
  
  do {
    for(i=0; i<v.size(); i++){
      cout << v[i] << endl;
    }
    
  } while(prev_permutation(v.begin(), v.end()));
  return 0;
}

Use next_permutation to permute elements until they are sorted

/* 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()
{
    vector<int> coll;
    INSERT_ELEMENTS(coll,1,3);
    PRINT_ELEMENTS(coll,"on entry:  ");
    /* permute elements until they are sorted
     * - runs through all permutations because the elements are sorted now
     */
    while (next_permutation(coll.begin(),coll.end())) {
        PRINT_ELEMENTS(coll," ");
    }
    PRINT_ELEMENTS(coll,"afterward: ");
}
on entry:  1 2 3
 1 3 2
 2 1 3
 2 3 1
 3 1 2
 3 2 1
afterward: 1 2 3