#ifndef permutation_h
#define permutation_h

#include <vector>
#include "bigint.h"

std::vector<bigint> permutation_gen(bigint);

class permutation {
  std::vector<bigint> pi;
public:
  permutation(bigint n) : pi(permutation_gen(n)) { }

  permutation(bigint n,bigint plus)
  {
    plus %= n;
    if (plus < 0) plus += n;
    for (bigint i = 0; i < n; i++)
      pi.push_back((i + plus) % n);
  }

  template<class T>
  void permute(std::vector<T> &v,bigint offset=0)
  {
    std::vector<T> w = v;
    
    for (bigint i = 0; i < pi.size(); i++)
      w.at(i + offset) = v.at(pi.at(i) + offset);
    
    for (bigint i = 0; i < v.size(); i++)
      v.at(i) = w.at(i);
  }
} ;

#endif