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.

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.

Nov 29, 2021 · 13-15) Initializer-list constructor. Constructs the container with the contents of the initializer list init, same as unordered_map(init.begin(), init.end()). 16-18) Constructs the container …

Nov 21, 2021 · std::unordered_set<Key,Hash,KeyEqual,Allocator>:: unordered_set C++ Containers library

Nov 27, 2023 · Classes unordered_set (C++11) collection of unique keys, hashed by keys (class template) [edit] unordered_multiset (C++11) collection of keys, hashed by keys (class template) [edit]

Dec 4, 2021 · Complexity Constant on average, worst case linear in the size of the container. Notes ... Example Run this code #include <cstddef> #include <functional> #include <iostream> #include …

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 …

Dec 4, 2021 · Complexity Given an instance c of unordered_map: 1,2) Average case: constant, worst case: c.size(). 3) Average case: std::distance(first, last), worst case: c.size(). 4) Average case: …

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 …

Nov 5, 2023 · Example Run this code #include <iostream> #include <unordered_set> int main () { std::unordered_set<int> example {1, 2, 3, 4}; for (int x : {2, 5}) if (example. contains(x)) std::cout << x …