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| #include <vector>
#include <numeric>
#include <string>
#include <iostream>
#include <algorithm>
#include <iterator>
template <typename T>
std::ostream& operator<< (std::ostream& out, const std::vector<T>& v) {
if ( !v.empty() ) {
out << '[';
std::copy (v.begin(), v.end(), std::ostream_iterator<T>(out, ", "));
out << "\b\b]";
}
return out;
}
class Partitioner
{
private:
using RGS_type = std::vector<unsigned int>; // Restricted Growth String
using id_type = unsigned int;
using set_type = std::vector<id_type>;
RGS_type a;
std::vector<RGS_type> m_partitions;
set_type m_set;
void visit(){
m_partitions.push_back(a);
}
void f(unsigned int mu, unsigned int nu, unsigned int sigma){
if(mu == 2){
visit();
}else{
f(mu-1, nu-1, (mu+sigma)%2);
}
if(nu == mu+1){
a[mu] = mu -1;
visit();
while(a[nu] > 0){
a[nu] = a[nu] - 1;
visit();
}
}else if(nu > mu + 1){
if((mu + sigma)%2 == 1){
a[nu - 1] = mu - 1;
}else{
a[mu] = mu -1;
}
if( (a[nu] + sigma) %2 == 1){
b(mu, nu - 1, 0);
}else{
f(mu, nu -1, 0);
}
while(a[nu] > 0){
a[nu] = a[nu] - 1;
if( (a[nu] + sigma) %2 == 1){
b(mu, nu - 1, 0);
}else{
f(mu, nu - 1, 0);
}
}
}
}
void b(unsigned int mu, unsigned int nu, unsigned int sigma){
if(nu == mu + 1){
while( a[nu] < mu - 1){
visit();
a[nu] = a[nu] + 1;
}
visit();
a[mu] = 0;
}else if( nu > mu + 1){
if( (a[nu] + sigma) %2 == 1){
f(mu, nu - 1, 0);
}else{
b(mu, nu -1, 0);
}
while( a[nu] < mu -1 ){
a[nu] = a[nu] + 1;
if( (a[nu] + sigma) %2 == 1){
f(mu, nu - 1, 0);
}else{
b(mu, nu - 1, 0);
}
}
if( (mu + sigma) %2 == 1){
a[nu - 1] = 0;
}else{
a[mu] = 0;
}
}
if(mu == 2) {
visit();
}else{
b(mu -1, nu-1, (mu +sigma)%2);
}
}
template<typename T>
set_type enumerate(T const& set){
std::vector<id_type> v(set.size());
std::iota(v.begin(), v.end(), 1);
return v;
}
public:
template<typename T>
Partitioner(T const& set) : m_set(enumerate(set)){}
Partitioner const& algorithm_u(unsigned int nb_blocks){
auto n = m_set.size();
a = RGS_type(n+1, 0);
for(unsigned int j = 1; j <= nb_blocks; ++j ){ a[n - nb_blocks + j] = j -1; }
f(nb_blocks, n, 0);
return *this;
}
auto begin() const {return m_partitions.begin();}
auto end() const {return m_partitions.end();}
}; |
Partager