template< class Key, class Hash, class KeyEqual, class Alloc > bool operator==( const std::unordered_multiset<Key,Hash,KeyEqual,Alloc>& lhs, const std::unordered_multiset<Key,Hash,KeyEqual,Alloc>& rhs );
template< class Key, class Hash, class KeyEqual, class Alloc > bool operator!=( const std::unordered_multiset<Key,Hash,KeyEqual,Alloc>& lhs, const std::unordered_multiset<Key,Hash,KeyEqual,Alloc>& rhs );
Compares the contents of two unordered containers.
The contents of two unordered containers
rhs are equal if the following conditions hold:
lhs.size() == rhs.size()
[lhs_eq1, lhs_eq2)obtained from
lhs.equal_range(lhs_eq1)has a corresponding group of equivalent elements in the other container
[rhs_eq1, rhs_eq2)obtained from
rhs.equal_range(rhs_eq1), that has the following properties:
std::distance(lhs_eq1, lhs_eq2) == std::distance(rhs_eq1, rhs_eq2).
std::is_permutation(lhs_eq1, lhs_eq2, rhs_eq1) == true.
The behavior is undefined if
Key is not EqualityComparable.
The behavior is also undefined if
key_eq() do (until C++20)
key_eq() does (since C++20) not have the same behavior on
rhs or if
Key is not a refinement of the partition into equivalent-key groups introduced by
key_eq() (that is, if two elements that compare equal using
operator== fall into different partitions).
|lhs, rhs||-||unordered containers to compare|
trueif the contents of the containers are equal,
trueif the contents of the containers are not equal,
Proportional to ΣSi2 calls to
value_type, calls to the predicate returned by
key_eq, and calls to the hasher returned by
hash_function in the average case, where S is the size of the ith equivalent key group. Proportional to N2 in the worst case, where N is the size of the container. Average case becomes proportional to N if the elements within each equivalent key group are arranged in the same order (happens when the containers are copies of each other).
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