Here are the equivalent implementations of upper_bound and lower_bound. This algorithm is O(log(n)) in the worst case, unlike the accepted answer which gets to O(n) in the worst case. Note that here high index is set to n instead of n – 1. These functions can return an index which is one beyond the bounds … Read more
In a sorted container, the last element that is less than or equivalent to x, is the element before the first element that is greater than x. Thus you can call std::upper_bound, and decrement the returned iterator once. (Before decrementing, you must of course check that it is not the begin iterator; if it is, … Read more
In a sorted container, the last element that is less than or equivalent to x, is the element before the first element that is greater than x. Thus you can call std::upper_bound, and decrement the returned iterator once. (Before decrementing, you must of course check that it is not the begin iterator; if it is, … Read more
If you have multiple elements in the range [first, last) whose value equals the value val you are searching for, then the range [l, u) where l = std::lower_bound(first, last, val) u = std::upper_bound(first, last, val) is precisely the range of elements equal to val within the range [first, last). So l and u are … Read more