n 取 r 逆時鐘旋轉排列法

#include <functional>   // std::function
#include <memory>       // std::shared_ptr
#include <vector>
#include <iostream>

using namespace std;

// n 取 r 做排列 
// 採用逆時旋轉排列法
// 必須 n >= r
class Permutation_nPr
{
  // 回報結果
  function<void(const shared_ptr<vector<unsigned char> > &, size_t)> m_Report; 
  // 放置要排列的數字
  shared_ptr <vector<unsigned char> > m_Digital_Array;
  // 要做排列的數目值
  size_t m_r;

  void v(size_t n, size_t r)
  {
    size_t i = n + 1;
    while (i--)
    {
      if (r == 0)
        m_Report(m_Digital_Array, m_r);
      else
        v(n - 1, r - 1);
      unsigned char tmp = m_Digital_Array->at(n);
      for (size_t j = n; j > 0; --j)
        m_Digital_Array->at(j) = m_Digital_Array->at(j - 1);
      m_Digital_Array->at(0) = tmp;
    }
  }

public:
  Permutation_nPr(
     const function<void(const shared_ptr<vector<unsigned char> > &, size_t)> 
      &Receive
  )
     :m_Report(Receive)

  {}

  void nPr(size_t n, size_t r)
  {
    m_r = r;

    m_Digital_Array = 
       shared_ptr<vector<unsigned char> >(new vector<unsigned char>(n));
    size_t i = n;
    while (i--)
    {
      m_Digital_Array->at(i) = i;
    }

    v(n - 1, r - 1);
  }
};

int N = 1;
void Show(const shared_ptr<vector<unsigned char> > &Digital_Array, size_t r)
{
  cout << N << ":\t";

  for (size_t i = Digital_Array->size() - 1; r > 0; --i, --r)
    cout << (int)Digital_Array->at(i) << ' ';
  cout << endl;
  ++N;
}

int main()
{
  Permutation_nPr P(Show);

  cout << "4P3 排列：" << endl;
  N = 1;
  P.nPr(4, 3);

  return 0;
}

n 取 n 逆時鐘旋轉排列法

#include <functional>   // std::function
#include <memory>       // std::shared_ptr
#include <vector>
#include <iostream>

using namespace std;

// n 取 n 做排列 
// 採用逆時旋轉排列法
class Permutation_nPn
{
  // 回報結果
  function<void(const shared_ptr<vector<unsigned char> > &)> m_Report;

  // 放置要排的數字
  shared_ptr <vector<unsigned char> > m_Digital_Array;

  void v(size_t n)
  {
    if (n == 0)
      m_Report(m_Digital_Array);
    else
    {
      size_t i = n + 1;
      while (i--)
      {
        v(n - 1);
        unsigned char tmp = m_Digital_Array->at(n);
        for (size_t j = n; j > 0; --j)
          m_Digital_Array->at(j) = m_Digital_Array->at(j - 1);
        m_Digital_Array->at(0) = tmp;
      }
    }
  }

public:
  Permutation_nPn(

    const function<void(const shared_ptr<vector<unsigned char> > &)> 
    &Receive
  )
    :m_Report(Receive)
  {}

  void nPn(size_t n)
  {
    m_Digital_Array = shared_ptr<vector<unsigned char> >(
      new vector<unsigned char>(n));
    size_t i = n;
    while (i)
    {
      m_Digital_Array->at(i - 1) = i - 1;
      --i;
    }

    v(n - 1);
  }
};

int N = 1;
void Show(const shared_ptr<vector<unsigned char> > &Digital_Array)
{
  cout << N << ":\t";
  
  for (size_t i = Digital_Array->size(); i > 0; --i)
    cout << (int)Digital_Array->at(i - 1) << ' ';
  cout << endl;
  ++N;
}

int main()
{
  Permutation_nPn P(Show);  

  cout << "4! 排列：" << endl;
  N = 1;
  P.nPn(4);

  return 0;
}