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.
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: unordered_map
Nov 29, 2021 · Define a const == operator for the class/struct and specialize std::hash// structure in the std namespacestd::unordered_map<std::string>={{(1)"One"}{2"Two"}{3"Three"}};// Option 3: Use …
Standard library header <unordered_set> (C++11) - Reference
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]
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_set<Key,Hash,KeyEqual,Allocator>:: contains
Nov 5, 2023 · #include <iostream>#include <unordered_set>int(){std::unordered_set<int>{1234};for(int:{25})if(contains())std::cout<<<<": …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: find
Dec 4, 2021 · (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: emplace
Dec 4, 2021 · (C++17) unordered_map::insert unordered_map::insert_range (C++23) unordered_map::insert_or_assign (C++17) unordered_map::emplace unordered_map::emplace_hint …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: insert
May 9, 2025 · (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) …
std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: erase
Dec 4, 2021 · #include <unordered_map>#include <iostream>int(){std::unordered_map<intstd::string>={{1"one"}{2"two"}{3"three"}{4"four"}{5"five"}{6"six"}};// …