vector存放pair對象

一般關聯對象都會放在map或者hash_map中，這樣做是爲了查詢速度快，SGISTL中map是紅黑樹結構，即每個節點要存放3個指針，分別是父節點，左子節點，右子節點，如果存入map的對象比較小且數量不多時，反而用有序vector會快一些。

 

例子demo：

typedef std::pair<string, int> Data; class DataCompare { public: bool operator()(const Data& lhs, const Data& rhs) const { return this->keyLess(lhs.first, rhs.first); } bool operator()(const Data& lhs, const Data::first_type& key) const { return this->keyLess(lhs.first, key); } bool operator()(const Data::first_type& key, const Data& rhs) const { return this->keyLess(key, rhs.first); } private: bool keyLess(const Data::first_type& lhs, const Data::first_type& rhs) const { return lhs < rhs; } }; void testVecMap() { std::vector<Data> vecData; typedef std::vector<Data>::iterator it_vec; vecData.push_back(Data("hong", 1)); vecData.push_back(Data("STL", 2)); vecData.push_back(Data("sportStl", 3)); std::sort(vecData.begin(), vecData.end(), DataCompare()); std::string strFind = "hong"; if (std::binary_search(vecData.begin(), vecData.end(), strFind, DataCompare())) { std::cout << "std::binary_search " << strFind << std::endl; } it_vec it = std::lower_bound(vecData.begin(), vecData.end(), strFind, DataCompare()); if (it != vecData.end() && !DataCompare()(strFind, *it)) { std::cout << "std::lower_bound " << strFind << std::endl; } std::pair<it_vec, it_vec> range = std::equal_range(vecData.begin(), vecData.end(), strFind, DataCompare()); if (range.first != range.second) { std::cout << "std::equal_range " << strFind << std::endl; } }