usingunordered_multimap=std::unordered_multimap<Key, T, Hash, Pred, std::pmr::polymorphic_allocator<std::pair<constKey,T>>>; } (2)(C++17 起) unordered_multimap 是无序关联容器,支持等价的关键(一个 unordered_multimap 可含有每个关
operators (std::set) operators (std::stack) operators (std::unordered_map) operators (std::unordered_multimap) operators (std::unordered_multiset) operators (std::unordered_set) operators (std::vector) remove_if remove_if std::array std::array::at std::array::back std::array::begin std...
operators (std::stack) operators (std::unordered_map) operators (std::unordered_multimap) operators (std::unordered_multiset) operators (std::unordered_set) operators (std::vector) remove_if remove_if std::array std::array::at std::array::back std::array::begin std::array::cbegin std:...
std::unordered_multimap template<classKey,// unordered_multimap::key_typeclassT,// unordered_multimap::mapped_typeclassHash= hash<Key>,// unordered_multimap::hasherclassPred = equal_to<Key>,// unordered_multimap::key_equalclassAlloc = allocator< pair<constKey,T> >// unordered_multimap::alloc...
>usingunordered_multimap= std::unordered_multimap<Key, T, Hash, Pred, std::pmr::polymorphic_allocator<std::pair<constKey, T>>>; } (2)(since C++17) std::unordered_multimapis an unordered associative container that supports equivalent keys (an unordered_multimap may contain multiple copies of...
参数 (无) 返回值 若容器为空则为true,否则为false 复杂度 常数。 示例 下列代码用empty检查std::unordered_multimap<int,int>是否含有任何元素: #include <unordered_map>#include <iostream>#include <utility>intmain(){std::unordered_multimap<int,int>numbers;std::cout<<"Initially, numbers.empty(): "...
using unordered_multimap = std::unordered_multimap<Key, T, Hash, Pred, std::pmr::polymorphic_allocator<std::pair<const Key,T>>>; }(2)(C++17 起) unordered_multimap 是无序关联容器,支持等价的关键(一个 unordered_multimap 可含有每个关键值的多个副本)和将关键与另一类型的值关联。 unordered_mult...
>usingunordered_multimap= std::unordered_multimap<Key, T, Hash, Pred, std::pmr::polymorphic_allocator<std::pair<constKey, T>>>; } (2)(since C++17) std::unordered_multimapis an unordered associative container that supports equivalent keys (an unordered_multimap may contain multiple copies of...
std::unordered_multimap<Key, T, Hash, KeyEqual, Alloc>::size_type erase_if(std::unordered_multimap<Key, T, Hash, KeyEqual, Alloc>&c, Pred pred); (since C++20) Erases all elements that satisfy the predicatepredfromc. Equivalent to ...
map中一个key只能存在一个,multimap中则可以存在多个key相同的value。 unordered_map是我们常说的hash_map,它的key也是唯一的, 所以你应该还会看到一个叫做unordered_multimap的东西。 std::set std::multiset std::map std::multimap 这几个东西都是基于binary tree的,具体地说是红黑树。