#ifndef BOOST_ALGORITHM_HPP

#define BOOST_ALGORITHM_HPP

#include <functional> // for plus and multiplies

#include <boost/config.hpp>

#include <boost/core/enable_if.hpp> // for boost::disable_if

#include <boost/type_traits/is_integral.hpp>

namespace boost { namespace algorithm {

template <typename T>

BOOST_CXX14_CONSTEXPR T identity_operation ( std::multiplies<T> ) { return T(1); }

template <typename T>

BOOST_CXX14_CONSTEXPR T identity_operation ( std::plus<T> ) { return T(0); }

template <typename T, typename Integer>

BOOST_CXX14_CONSTEXPR typename boost::enable_if<boost::is_integral<Integer>, T>::type

power (T x, Integer n) {

T y = 1; // Should be "T y{1};"

if (n == 0) return y;

while (true) {

if (n % 2 == 1) {

y = x * y;

if (n == 1)

return y;

}

n = n / 2;

x = x * x;

}

return y;

}

template <typename T, typename Integer, typename Operation>

BOOST_CXX14_CONSTEXPR typename boost::enable_if<boost::is_integral<Integer>, T>::type

power (T x, Integer n, Operation op) {

T y = identity_operation(op);

if (n == 0) return y;

while (true) {

if (n % 2 == 1) {

y = op(x, y);

if (n == 1)

return y;

}

n = n / 2;

x = op(x, x);

}

return y;

}

}}

#endif // BOOST_ALGORITHM_HPP