25 Algorithms library [algorithms]

25.4 Sorting and related operations [alg.sorting]

25.4.3 Binary search [alg.binary.search]

25.4.3.1 lower_bound [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 any iterator j in the range [first,i) the following corresponding conditions hold: *j < value or comp(*j, value) != false.

Complexity: At most log2(last - first) + Ο(1) comparisons.