#include<iterator>
template<typename T, typename Iterator>
Iterator FindImpl(const T &value,
Iterator first,
Iterator last,
std::random_access_iterator_tag) {
auto if_no = last;
last--;
while (first < last) {
Iterator mid = (last - first) / 2 + first;
if (*mid < value) {
first = mid + 1;
} else {
last = mid;
}
}
if (*first == value) {
return first;
}
return if_no;
}
template<typename T, typename Iterator>
Iterator FindImpl(const T &value,
Iterator first,
Iterator last,
std::bidirectional_iterator_tag) {
while (first != last) {
if (*first == value) {
return first;
}
first++;
}
return last;
}
template<typename T, typename Iterator>
Iterator Find(const T &value, Iterator first, Iterator last) {
return FindImpl(value,
first,
last,
typename std::iterator_traits<Iterator>::iterator_category());
}