#ifndef PERMUTATION_H
#define PERMUTATION_H

#include <vector>

// permutation with fixpoint pi[0]=0
class permutation {
  public:
    permutation(int size); // initialize to identity
    void transpose(int i, int j);
    void random();
    int operator[](int i); // return the image of i (i and its image 0-based)
    bool check(); // check invariant : sigma[0] = 0 and it is a permutation
    int get_size();
    friend permutation permutation_crossover(permutation &a, permutation &b);
  protected:
    int size;
    std::vector<int> sigma; // sigma[i] is the image of i
};

permutation permutation_crossover(permutation &a, permutation &b);

#endif // PERMUTATION_H