3.0 KiB
[lower.bound]
26 Algorithms library [algorithms]
26.8 Sorting and related operations [alg.sorting]
26.8.4 Binary search [alg.binary.search]
26.8.4.2 lower_bound [lower.bound]
`template<class ForwardIterator, class T = iterator_traits::value_type> constexpr ForwardIterator lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
template<class ForwardIterator, class T = iterator_traits::value_type, class Compare> constexpr ForwardIterator lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
template<forward_iterator I, sentinel_for S, class Proj = identity, class T = projected_value_t<I, Proj>, indirect_strict_weak_order<const T*, projected<I, Proj>> Comp = ranges::less> constexpr I ranges::lower_bound(I first, S last, const T& value, Comp comp = {}, Proj proj = {}); template<forward_range R, class Proj = identity, class T = projected_value_t<iterator_t, Proj>, indirect_strict_weak_order<const T*, projected<iterator_t, Proj>> Comp = ranges::less> constexpr borrowed_iterator_t ranges::lower_bound(R&& r, const T& value, Comp comp = {}, Proj proj = {}); `
Let comp be less{} andproj be identity{} for overloads with no parameters by those names.
Preconditions: The elements e of [first, last) are partitioned with respect to the expression
bool(invoke(comp, invoke(proj, e), value)).
Returns: The furthermost iterator i in the range [first, last] such that for every iterator j in the range [first, i),bool(invoke(comp, invoke(proj, *j), value)) is true.
Complexity: At most log2(last - first)+O(1) comparisons and projections.