gistfile1.cpp

template <int Begin, int End, int Size, class Enable=void> 
struct partition;

template <int BeginIt, int EndIt, int Size>
struct partition<BeginIt, EndIt, Size, typename std::enable_if<(BeginIt<EndIt)>::type> {

	template <class T>
	inline static void go(T* vec, const T& pivot) {

		if (vec[BeginIt] <= pivot) {
			return partition<BeginIt+1, EndIt, Size>::go(vec, pivot);
		}

		if (vec[EndIt-1] > pivot) {
			return partition<BeginIt, EndIt-1, Size>::go(vec, pivot);
		}

		std::swap(vec[BeginIt], vec[EndIt-1]);
		partition<BeginIt+1, EndIt-1, Size>::go(vec, pivot);
	}
};

template <int BeginIt, int EndIt, int Size>
struct partition<BeginIt, EndIt, Size, typename std::enable_if<(BeginIt>=EndIt)>::type > {
	
	template <class T>
	inline static void go(T* vec, const T& pivot) {
		constexpr int pivot_idx = BeginIt-1;

		std::swap(vec[0], vec[pivot_idx]);
		quicksort(vec, int_<pivot_idx>());
		quicksort(vec+pivot_idx+1, int_<Size-(pivot_idx+1)>());

	}
};

template <int Val>
class int_{ };

template <class T, int Size>
inline auto quicksort( T* vec, const int_<Size>& ) -> typename std::enable_if<(Size>=1)>::type {
	partition<1,Size,Size>::go(vec, vec[0]);
}

template <class T, int Size>
inline auto quicksort( T* vec, const int_<Size>& ) -> typename std::enable_if<(Size<1)>::type { }