class LRUCache {
private:
    int maxSize;
    list<pair<int,int> > cache;
    unordered_map<int, list<pair<int,int> >::iterator> m;
public:
    LRUCache(int capacity): maxSize(capacity) {

    }

    int get(int key) {
        auto it = m.find(key);
        if(it == m.end()){
            return -1;
        }
        cache.push_front(*(it->second));
        cache.erase(it->second);
        m[key] = cache.begin();
        return it->second->second;
    }

    void put(int key, int value) {
        auto it = m.find(key);
        if(it != m.end()){
            cache.erase(it->second);
        }
        cache.push_front({key,value});
        m[key] = cache.begin();
        if(cache.size() > maxSize){
            auto it = cache.rbegin();
            m.erase(it->first);
            cache.pop_back();
        }
    }
};

/**
 * Your LRUCache object will be instantiated and called as such:
 * LRUCache* obj = new LRUCache(capacity);
 * int param_1 = obj->get(key);
 * obj->put(key,value);
 */