Can someone please explain me lower_bound and upper_bound and how they are used in sorted array? Please explain in depth.
Can someone please explain me lower_bound and upper_bound and how they are used in sorted array? Please explain in depth.
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int* ptr = lower_bound(a, a + n, k);returns the pointer to the first element in
athat is larger than or equal to kint* ptr = upper_bound(a, a + n, k);returns the pointer to the first element in
athat is larger than kYou can use the following to get the index. This also means "how many elements in a are smaller than k"
int index = lower_bound(a, a + n, k) - a;Don't forget that
std::mapandstd::sethave their ownlower_boundandupper_boundfunction.According to cplusplus.com
lower_bound(a,a+n,k)returns pointer to the first element, where k can be inserted.upper_bound(a,a+n,k)returns pointer to the last element, where k can be inserted :).