LFUCache(int capacity): capacity(capacity) {

freqList.emplace_back(std::pair<int, std::list<int>>(1, {}));

}

int get(int key);

void put(int key, int value);

int capacity;

struct Item {

int val;

std::list<std::pair<int, std::list<int>>>::iterator freqIt;

std::list<int>::iterator timeIt;

};

std::unordered_map<int, Item> mp;

// 二维双向链表，第一维按frequency降序，第二维按access time降序

std::list<std::pair<int, std::list<int>>> freqList;

void reorderList(Item &);