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 · 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 …

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]

Jul 5, 2021 · (C++20) unordered_map::equal_range Bucket interface unordered_map::begin(size_type)unordered_map::cbegin(size_type) …

Feb 22, 2025 · Unordered associative containers (since C++11) Unordered associative containers implement unsorted (hashed) data structures that can be quickly searched (O (1) average, O (n) …

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 …

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 …

Dec 4, 2021 · (C++17) Lookup unordered_map::at unordered_map::operator [] unordered_map::count unordered_map::find unordered_map::contains (C++20) unordered_map::equal_range Bucket …

Nov 5, 2023 · #include <iostream>#include <unordered_set>int(){std::unordered_set<int>{1234};for(int:{25})if(contains())std::cout<<<<": …