// Copyright (C) 2005, Ondra Kamenik

// $Id: pascal_triangle.h 762 2006-05-22 13:00:07Z kamenik $

#ifndef PASCAL_TRIANGLE_H
#define PASCAL_TRIANGLE_H

#include <vector>

namespace ogu
{

  using std::vector;

  class PascalRow : public vector<int>
  {
    int k;
  public:
    PascalRow()
      : vector<int>(), k(1)
    {
      push_back(2);
    }
    void setFromPrevious(const PascalRow &prev);
    void prolong(const PascalRow &prev);
    void prolongFirst(int n);
    void print() const;
  };

  class PascalTriangle
  {
    vector<PascalRow> tr;
  public:
    PascalTriangle()
    {
      tr.push_back(PascalRow());
    }
    PascalTriangle(const PascalTriangle &triang)
      : tr(triang.tr)
    {
    }
    const PascalTriangle &
    operator=(const PascalTriangle &triang)
    {
      tr = triang.tr; return *this;
    }
    int noverk(int n, int k);
    void print() const;
  protected:
    void ensure(int n, int k);
    int max_n() const;
    int max_k() const;
  };
};

extern ogu::PascalTriangle ptriang;

#endif

// Local Variables:
// mode:C++
// End: