在其他答案中还有一个尚未讨论的附加问题,它适用于std::map以及std::unordered_map、std::setstd::unordered_set: insert与键对象一起使用,这意味着如果容器中已经存在键,则不需要分配节点。 emplace需要先构造key,一般每次调用都需要分配一个节点。 从这个角度来看,如果密钥已经存在于容器中,emplace的效率可能低于in...
typedef void (*Command)(void); typedef std::unordered_map<std::string, Command> cmdMap; class Bot { public: Bot(); void Run(); private: std::vector<std::string> userCmd; std::vector<std::string> cmdNames; cmdMap funcList; void PrintBotMenu(); void GetUserInput(); void CallCmd(...
我总是更喜欢 try_emplace 而不是 emplace。一个关键的区别是 try_emplace 不会构造与键关联的对象,如果键已经存在。这将提高性能,以防该类型对象的创建成本很高例如下面的代码(来自 https://github.com/PacktPublishing/Cpp17-STL-Cookbook/blob/master/Chapter02/efficient_insert_or_reassign_to_map.cpp 的示例...
N4279 insert_or_assign()/try_emplace() For map/unordered_map VS 2015 14 N4280 size(), empty(), data() VS 2015 14 N4366 Precisely Constraining unique_ptr Assignment VS 2015 14 N4387 Improving pair And tuple VS 2015.2 14 N4389 bool_constant VS 2015 14 N4508 sha...
C. Equal Sums map映射 You are given k sequences of integers. The length of the i -th sequence equals to n i . You have to choose exactly two sequences i and j ( i ≠ j ) such that you can remove exactly one element in each of them in such a way that the sum of the ...
{ int a; string b = "label"; }; struct Comparer { bool operator() (K a, K b) { return a.a < b.a; } }; map<K, double, Comparer> m; K const s1{1}; K const s2{2}; K const s3{3}; int main() { m.emplace(s1, 1.08); m.emplace(s2, 3.14); m.emplace(s3, 5.21...
{ std::map<cmGeneratorTarget const*, size_t>::value_type value(gt, 0); auto insertion = this->TargetOrderIndex.insert(value); if (!insertion.second) { return; } auto entry = insertion.first; const auto& deps = this->GetTargetDirectDepends(gt); for (const auto& d : deps) ...
insert_quant_dequant.cpp serialization pickler.cpp python_print.cpp 50 changes: 25 additions & 25 deletions 50 aten/src/ATen/MapAllocator.cpp Show comments View file Edit file Delete file This file contains bidirectional Unicode text that may be interpreted or compiled differently than ...
N4279 insert_or_assign()/try_emplace() For map/unordered_map VS 2015 14 N4280 size(), empty(), data() VS 2015 14 N4366 Precisely Constraining unique_ptr Assignment VS 2015 14 N4387 Improving pair And tuple VS 2015.2 14 N4389 bool_constant VS 2015 14 N4508 sha...
N4279 insert_or_assign()/try_emplace() For map/unordered_map VS 2015 14 N4280 size(), empty(), data() VS 2015 14 N4366 Precisely Constraining unique_ptr Assignment VS 2015 14 N4387 Improving pair And tuple VS 2015.2 14 N4389 bool_constant VS 2015 14 N4508 sha...