LeetCode -- LRU Cache

关于LRU的具体定义可以查看这个链接：

http://mcicpc.cs.atu.edu/archives/2012/mcpc2012/lru/lru.html

public class LRUCache {


    private Dictionary<int, int> _cache; 
	private List<int> _usedKeys;
	
	private int _capacity;
	
    public LRUCache(int capacity)
	{
		_cache = new Dictionary<int, int>();
		_usedKeys = new List<int>();
		
        _capacity = capacity;
    }


    public int Get(int key)
	{
        if(!_cache.ContainsKey(key)){
			return -1;
		}
		else{
			_usedKeys.Remove(key);
			_usedKeys.Insert(0, key);
			
			return _cache[key];
		}
    }


    public void Set(int key, int value) 
	{
		if(_cache.ContainsKey(key)){
			_cache[key] = value;
			
			_usedKeys.Remove(key);
			_usedKeys.Insert(0, key);
		}
		else{
			if(_cache.Keys.Count < _capacity){
				_cache.Add(key, value);
				
				_usedKeys.Insert(0, key);
			}
			else
			{
				var removing = _usedKeys.Last();
				_usedKeys.RemoveAt(_usedKeys.Count - 1);
				
				_cache.Remove(removing);
				_cache.Add(key, value);
				
				_usedKeys.Insert(0, key);
			}
		}
    }
    
}

LeetCode -- LRU Cache

原文：http://blog.csdn.net/lan_liang/article/details/49962311