LRU: C++代码实现

Posted 2022-10-29 敲代码的Messi

#include <list>
#include <unordered_map>
#include <utility>
using namespace std;

class LRUCache


private:
    int _cap = 0;
    list<pair<int, int>> _cache;
    unordered_map<int, list<pair<int, int>>::iterator> _map;
public:
    int get(int key)
    
        if (_map.count(key) > 0)
        
            auto temp = *_map[key];
            _cache.erase(_map[key]);
            _cache.push_front(temp);
            _map[key] = _cache.begin();
            return temp.second;
        
        return -1;   
    
    
    void put(int key, int value)
    
        if ( _map.count(key) > 0)
        
            _cache.erase(_map[key]);
            _map.erase(key);
        
        else if(_cache.size() == _cap)
        
            _cache.pop_back();
            _map.erase(key);
        
        
        _cache.push_front(pair<int, int>(key,value));
        _map[key] = _cache.begin();
    
;