The maximum number of children of a node in the heap depends on the type of heap. Let’s say if X is a parent node of Y, then the value of X follows some specific order with respect to value of Y and the same order will be followed across the tree. If not, only end() and any elements erased.A heap is a specific tree based data structure in which all the nodes of tree are in a specific order. If the vector changed capacity, all of them. If not, only those at or after the insertion point (including end()). If not, none.Įrased elements and all elements after them (including end()). The standard library provides a specialization of std::vector for the type bool, which may be optimized for space efficiency. The behavior is undefined (until C++20) The program is ill-formed (since C++20) if Allocator::value_type is not the same as T.

The type must meet the requirements of Allocator. This container (but not its members) can be instantiated with an incomplete element type if the allocator satisfies the allocator completeness requirements.Īn allocator that is used to acquire/release memory and to construct/destroy the elements in that memory. Generally, it is required that element type meets the requirements of Erasable, but many member functions impose stricter requirements. The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type is a complete type and meets the requirements of Erasable, but many member functions impose stricter requirements. T must meet the requirements of CopyAssignable and Cop圜onstructible.

↑ In libstdc++, shrink_to_fit() is not available in C++98 mode.

However, std::vector objects generally cannot be constexpr, because any dynamically allocated storage must be released in the same evaluation of constant expression. Member functions of std::vector are constexpr: it is possible to create and use std::vector objects in the evaluation of a constant expression. Std::vector (for T other than bool) meets the requirements of Container, AllocatorAwareContainer (since C++11), SequenceContainer, ContiguousContainer (since C++17) and ReversibleContainer.

Insertion or removal of elements - linear in the distance to the end of the vector 𝓞(n).

Insertion or removal of elements at the end - amortized constant 𝓞(1).

The complexity (efficiency) of common operations on vectors is as follows: The reserve() function can be used to eliminate reallocations if the number of elements is known beforehand. Reallocations are usually costly operations in terms of performance. Extra memory can be returned to the system via a call to shrink_to_fit(). The total amount of allocated memory can be queried using capacity() function.

This way a vector does not need to reallocate each time an element is inserted, but only when the additional memory is exhausted. Vectors usually occupy more space than static arrays, because more memory is allocated to handle future growth. The storage of the vector is handled automatically, being expanded as needed. This means that a pointer to an element of a vector may be passed to any function that expects a pointer to an element of an array. The elements are stored contiguously, which means that elements can be accessed not only through iterators, but also using offsets to regular pointers to elements. 2) std::pmr::vector is an alias template that uses a polymorphic allocator.

Enqueue time complexity