Permutation1

Interface

Class Permutation1

This class progressively generates all the permutations of the given size, while also giving the possibility to return the rank and parity of the current permutation.

References:

SUBSET, a C++ library of combinatorial routines, http://www.csit.fsu.edu/~burkardt/cpp_src/subset/subset.html

Example 1

#include <codecogs/maths/combinatorics/permutations/permutation1.h>
#include <iostream>
int main()
{
  Maths::Combinatorics::Permutations::Permutation1 P(3);
  std::cout << "The permutations of 3 elements:";
  std::cout << std::endl;
  for (int i = 0; i < 6; i++)
  {
    std::vector<int> alpha = P.getNext();
    for (int j = 0; j < alpha.size(); j++)
      std::cout << alpha[j] << " ";
    if (P.isEven())
      std::cout << "\tis even";
    else
      std::cout << "\tis odd";
    std::cout << "\t rank = " << P.getRank();
    std::cout << std::endl;
  }
  return 0;
}

Output

The permutations of 3 elements:
1 2 3   is even  rank = 1
2 1 3   is odd   rank = 2
3 1 2   is even  rank = 3
1 3 2   is odd   rank = 4
2 3 1   is even  rank = 5
3 2 1   is odd   rank = 6

Authors

Lucian Bentea (August 2005)

Source Code

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