Internally, the elements in the unordered_set are not sorted in any particular order, but organized into buckets depending on their hash values to allow for fast access to individual elements directly by their values (with a constant average time complexity on average). unordered_set containers ar...
{2,7,1,8,2,8};// creates a set of intsprint(mySet);mySet.insert(5);// puts an element 5 in the setprint(mySet);if(autoiter=mySet.find(5);iter!=mySet.end())mySet.erase(iter);// removes an element pointed to by iterprint(mySet);mySet.erase(7);// removes an element ...
Time Complexity Average case: Linear in the number of elements removed for version 1 and version 2. Worst case: Linear in the container size.. Example: In the example below, theunordered_set::erasefunction is used to delete a single element fromuSet. ...
C++11 unordered_set::erase C++11 unordered_set::find C++11 unordered_set::get_allocator C++11 unordered_set::hash_function C++11 unordered_set::insert C++11 unordered_set::key_eq C++11 unordered_set::load_factor C++11 unordered_set::max_bucket_count C++11 unordered_set::max_lo...
Complexity Constant. Iterator validity All iterators, pointers and references remain valid, but now are referring to elements in the other container, and iterate in it. non-member overloads: operators (unordered_set) swap (unordered_set)
<unordered_set> std::unordered_set::begin container iterator (1) iterator begin() noexcept;const_iterator begin() const noexcept; bucket iterator (2) local_iterator begin ( size_type n );const_local_iterator begin ( size_type n ) const; ...
But in the worst-case scenario, the unordered_map is slower than a map because the worst time complexity of all the operations in an unordered_map (O(n)) is greater than the time complexity for all the operations in a map (O(log n)). ...
erase_if(std::unordered_set) (C++20) Deduction guides(C++17) template< class... Args > iterator emplace_hint( const_iterator hint, Args&&... args ); (since C++11) Inserts a new element into the container, using hint as a suggestion where the element should go. The constructors of...
Example #include<iostream>#include<unordered_set>using namespace std;intmain(){// 1. initialize a hash setunordered_set<int>hashset;// 2. insert a new keyhashset.insert(1);hashset.insert(2);hashset.insert(3);// 3. delete a keyhashset.erase(2);// 4. check if the key is in ...
C++11 unordered_set::erase C++11 unordered_set::find C++11 unordered_set::get_allocator C++11 unordered_set::hash_function C++11 unordered_set::insert C++11 unordered_set::key_eq C++11 unordered_set::load_factor C++11 unordered_set::max_bucket_count C++11 unordered_set::max_lo...