C++ Essentials 之 lower_bound 和 upper_bound 的比较函数格式不同

第一次注意到这个问题。

cppreference 上的条目：
lower_bound
upper_bound

C++17 草案 N4659

lower_bound

template<class ForwardIterator, class T>
ForwardIterator
lower_bound(ForwardIterator first, ForwardIterator last, const T& value);

template<class ForwardIterator, class T, class Compare>
ForwardIterator
lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);

Requires: The elements e of [first, last) shall be partitioned with respect to the expression e < value or comp(e, value).

Returns: The furthermost iterator i in the range [first, last] such that for every iterator j in the
range [first, i) the following corresponding conditions hold: *j < value or comp(*j, value) != false.

upper_bound

template<class ForwardIterator, class T>
ForwardIterator
upper_bound(ForwardIterator first, ForwardIterator last, const T& value);

template<class ForwardIterator, class T, class Compare>
ForwardIterator
upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);

Requires: The elements e of [first, last) shall be partitioned with respect to the expression !(value < e) or !comp(value, e).

Returns: The furthermost iterator i in the range [first, last] such that for every iterator j in the
range [first, i) the following corresponding conditions hold: !(value < *j) or comp(value, *j) == false.