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- #ifndef BINARY_SEARCH_DWA_122600_H_
- # define BINARY_SEARCH_DWA_122600_H_
- # include <boost/detail/iterator.hpp>
- # include <utility>
- namespace boost { namespace detail {
- template <class ForwardIter, class Tp>
- ForwardIter lower_bound(ForwardIter first, ForwardIter last,
- const Tp& val)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
-
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (*middle < val) {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- else
- len = half;
- }
- return first;
- }
- template <class ForwardIter, class Tp, class Compare>
- ForwardIter lower_bound(ForwardIter first, ForwardIter last,
- const Tp& val, Compare comp)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (comp(*middle, val)) {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- else
- len = half;
- }
- return first;
- }
- template <class ForwardIter, class Tp>
- ForwardIter upper_bound(ForwardIter first, ForwardIter last,
- const Tp& val)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (val < *middle)
- len = half;
- else {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- }
- return first;
- }
- template <class ForwardIter, class Tp, class Compare>
- ForwardIter upper_bound(ForwardIter first, ForwardIter last,
- const Tp& val, Compare comp)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (comp(val, *middle))
- len = half;
- else {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- }
- return first;
- }
- template <class ForwardIter, class Tp>
- std::pair<ForwardIter, ForwardIter>
- equal_range(ForwardIter first, ForwardIter last, const Tp& val)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle, left, right;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (*middle < val) {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- else if (val < *middle)
- len = half;
- else {
- left = boost::detail::lower_bound(first, middle, val);
- std::advance(first, len);
- right = boost::detail::upper_bound(++middle, first, val);
- return std::pair<ForwardIter, ForwardIter>(left, right);
- }
- }
- return std::pair<ForwardIter, ForwardIter>(first, first);
- }
- template <class ForwardIter, class Tp, class Compare>
- std::pair<ForwardIter, ForwardIter>
- equal_range(ForwardIter first, ForwardIter last, const Tp& val,
- Compare comp)
- {
- typedef detail::iterator_traits<ForwardIter> traits;
- typename traits::difference_type len = boost::detail::distance(first, last);
- typename traits::difference_type half;
- ForwardIter middle, left, right;
- while (len > 0) {
- half = len >> 1;
- middle = first;
- std::advance(middle, half);
- if (comp(*middle, val)) {
- first = middle;
- ++first;
- len = len - half - 1;
- }
- else if (comp(val, *middle))
- len = half;
- else {
- left = boost::detail::lower_bound(first, middle, val, comp);
- std::advance(first, len);
- right = boost::detail::upper_bound(++middle, first, val, comp);
- return std::pair<ForwardIter, ForwardIter>(left, right);
- }
- }
- return std::pair<ForwardIter, ForwardIter>(first, first);
- }
- template <class ForwardIter, class Tp>
- bool binary_search(ForwardIter first, ForwardIter last,
- const Tp& val) {
- ForwardIter i = boost::detail::lower_bound(first, last, val);
- return i != last && !(val < *i);
- }
- template <class ForwardIter, class Tp, class Compare>
- bool binary_search(ForwardIter first, ForwardIter last,
- const Tp& val,
- Compare comp) {
- ForwardIter i = boost::detail::lower_bound(first, last, val, comp);
- return i != last && !comp(val, *i);
- }
- }}
- #endif
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