std:: unordered_map - cppreference.com
Apr 26, 2025 · std::unordered_map is an associative container that contains key-value pairs with unique keys. Search, insertion, and removal of elements have average constant-time complexity.
std:: unordered_set - cppreference.com
Apr 26, 2025 · std::unordered_set is an associative container that contains a set of unique objects of type Key. Search, insertion, and removal have average constant-time complexity.
Standard library header <unordered_set> (C++11) - Reference
Nov 27, 2023 · Contents 1Includes 2Classes 3Functions 3.1Range access 4Synopsis 4.1Class template std::unordered_set 4.2Class template std::unordered_multiset <compare> (C++20) Three-way …
std::unordered_set<Key,Hash,KeyEqual,Allocator>:: unordered_set
Nov 21, 2021 · Constructs new container from a variety of data sources. Optionally uses user supplied bucket_count as a minimal number of buckets to create, hash as the hash function, equal as the …
std::unordered_set<Key,Hash,KeyEqual,Allocator>:: insert
May 9, 2025 · The value_type must be EmplaceConstructible into unordered_set from std::forward<K>(obj). This overload participates in overload resolution only if Hash and KeyEqual are …
std:: unordered_multimap - cppreference.com
Apr 26, 2025 · std::unordered_multimap is an unordered associative container that supports equivalent keys (an unordered_multimap may contain multiple copies of each key value) and that associates …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: find
Dec 4, 2021 · This overload participates in overload resolution only if Hash and KeyEqual are both transparent. This assumes that such Hash is callable with both K and Key type, and that the …
std::unordered_set<Key,Hash,KeyEqual,Allocator>:: contains
Nov 5, 2023 · 1) Checks if there is an element with key equivalent to key in the container.
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: emplace
Dec 4, 2021 · The constructor of the new element (i.e. std::pair<const Key, T>) is called with exactly the same arguments as supplied to emplace, forwarded via std::forward<Args>(args).... The element …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: insert
May 9, 2025 · Inserts element (s) into the container, if the container doesn't already contain an element with an equivalent key.