unordered_map/set自定义哈希函数

Posted 2022-11-25 goto_1600

struct pairhash 
public:
    template <typename T, typename U>
    std::size_t operator()(const std::pair<T, U> &x) const
    
        return std::hash<T>()(x.first) ^ std::hash<U>()(x.second);
    
;

class abc 
    std::unordered_map<std::pair<int,int>, int, pairhash> rules;
;


struct c_hash 
    inline size_t operator()(const tuple<int,int,int> & p) const 
        return get<0>(p) * 100 + get<1>(p)*10 + get<2>(p); 
    
;
int main()
	unordered_set<tuple<int,int,int>,c_hash>s;   
	s.insert(make_tuple(1,2,3));
	return 0;