LRUCache.cs - https://leetcode.com/problems/lru-cache/

LRUCache.cs

public class LRUCache 
{
    private readonly int _capacity;
    private readonly IDictionary<int, LinkedListNode<Tuple<int, int>>> _store = new Dictionary<int, LinkedListNode<Tuple<int, int>>>();
    private LinkedList<Tuple<int, int>> _accessLog = new LinkedList<Tuple<int, int>>();
    
    public LRUCache(int capacity) 
    {
        _capacity = capacity;
    }
    
    public int Get(int key)
    {
        LinkedListNode<Tuple<int, int>> val;
        if(_store.TryGetValue(key, out val)) 
        {
            _accessLog.Remove(val);
            _accessLog.AddLast(val);
            
            return val.Value.Item2;
        }
        
        return -1;
    }
    
    public void Put(int key, int value)
    {            
        var val = new LinkedListNode<Tuple<int, int>>(Tuple.Create(key, value));
        if(!_store.ContainsKey(key))
        {
            if(_store.Count == _capacity) 
            {
                _store.Remove(_accessLog.First.Value.Item1);
                _accessLog.RemoveFirst();
            }
            
            _store.Add(key, val);
            _accessLog.AddLast(val);
        }
        else 
        {
            var previousValue = _store[key];
            _accessLog.Remove(previousValue);
            
            _store[key] = val;
            _accessLog.AddLast(val);
        }
    }
}