#pragma once

#include <vector>
#include <cstddef>

template<class It>
class IteratorRange {
 public:
  IteratorRange(It b, It e) : begin_(b), end_(e), size_(std::distance(b, e)) {}

  typedef It iterator;

  It begin() const {
    return begin_;
  }

  It end() const {
    return end_;
  }

  std::size_t size() const {
    return size_;
  }
 private:
  It begin_, end_;
  std::size_t size_;
};

template <typename It>
class Slicer {
 public:
  Slicer(It begin, It end, int page_size) : begin_(begin), end_(end), page_size(page_size) {
    while (std::distance(begin, end)>=page_size) {
      auto temp = begin;
      advance(begin, page_size);
      pages_.push_back(IteratorRange<It>(temp, begin));
    }
    if (begin != end) {
      pages_.push_back(IteratorRange<It>(begin, end));
    }
  }
  typename std::vector<IteratorRange<It>>::iterator begin() {
    return pages_.begin();
  }
  typename std::vector<IteratorRange<It>>::iterator end() {
    return pages_.end();
  }
  std::size_t size() const {
    return pages_.size();
  }
 private:
  It begin_, end_;
  int page_size;
  std::vector<IteratorRange<It>> pages_;
};

template <typename C>
Slicer<typename C::iterator> Slice(C& c, std::size_t page_size) {
  return Slicer<typename C::iterator>(c.begin(), c.end(), page_size);
}

template <typename C>
Slicer<typename C::const_iterator> Slice(const C& c, std::size_t page_size) {
  return Slicer<typename C::const_iterator>(c.begin(), c.end(), page_size);
}