方法二:哈希表 classSolution{public:vector<int>twoSum(vector<int>& nums,inttarget){ unordered_map<int,int> hashtable;for(inti =0; i < nums.size(); ++i) {autoit = hashtable.find(target - nums[i]);if(it != hashtable.end()) {return{it->second, i}; } hashtable[nums[i]] = i...
1 #include <hash_map> 2 using namespace stdext; 3 hash_map<int ,int> myhash; 在GCC中编译: 1 #include <ext/hash_map> 2 using namespace __gnu_cxx; 3 hash_map<int ,int> myhash; 既如此,还是用unordered_map吧! C++ 11标准中加入了unordered系列的容器。unordered_map记录元素的hash值,根...
using namespace std; int main() { map<char,int> mp; mp['m']=20; mp['r']=30; mp['a']=40; for(map<char,int>::iterator it=mp.begin();it!=mp.end();it++) cout<<it->first<<' '<<it->second<<endl; return 0; } //输出时,map会以键从小到大的顺序自动排序 a 40 m 20 ...
return std::hash<int>()(empl.m_id); } std::size_t operator()(int id) const { return std::hash<int>()(id); } }; int main() { // Use std::equal_to<> which will automatically deduce and forward the parameters tsl::sparse_map<employee, int, hash_employee, std::equal_to<>>...
unordered_map<int, int> hash; vector<int> result; for (int i = 0; i < numbers.size(); i++) { int numberToFind = target - numbers[i]; //if numberToFind is found in map, return them if (hash.find(numberToFind) != hash.end()) { result.push_back(hash[numberToFind]); res...
map<int, int> m; unordered_map<int, int> um; hash_map<int, int> hm; // 初始化 for (int i = 0; i<size; i++) { m[i] = i; um[i] = i; hm[i] = i; } // map的查找 { int count = 0; progress_timer t; // progress_timer变量会在创建时计时,析构时自动打印出耗时,所...
unordered_map容器的底层实现是Hash Table,元素乱序存储,但增删改查效率极高,复杂度均为 O(1) 代码语言:javascript 复制 unordered_map<string, int> unMap; cout << "unordered_map中的key值无序(底层哈希表实现):" << endl; unMap["B"] = 22; unMap["A"] = 11; unMap["D"] = 44; unMap["C"...
int main() { std::multimap<string, std::string> studentMap2 = { {"first", "Tom"}, {"second", "Mali"}, {"third", "John"}}; studentMap2.insert(std::pair<std::string, std::string>("first", "Bob")); std::multimap<std::string, std::string>::iterator itor_begin = student...
对于其他类型,比如int,char,short,double等,我们直接强转为size_t,这样就可以完成哈希映射。 字符串转换为整型的场景还是比较常见的,网上有很多关于字符串哈希的算法,我们取最优的算法,思路就是将每一个字符对应的ascll码分别拆下来,每次的hash值都为上一次的hash值×131后再加上字符的ascll码值,遍历完字符串后,...
#include <iostream>#include <unordered_map>int main() {std::unordered_map<int, std::string> map;// 预留足够的桶空间map.reserve(100); // 预留至少能容纳 100 个元素的桶空间// 添加一些元素for (int i = 0; i < 100; ++i) {map[i] = "Value " + std::to_string(i);}// 获取当前...