Java LRU的實現

最近在leetcode上作題的時，看到了一道有關LRU Cache的題目，正好我當初面試阿里巴巴的時候問到的。主要採用linkedHashMap來實現。

 

package edu.test.algorithm;

import java.util.LinkedHashMap;

public class LRUCache {
    LinkedHashMap<Integer,Integer> linkedHashMap;
    int capacity;
    public LRUCache(int capacity) {
        linkedHashMap=new LinkedHashMap<Integer, Integer>(capacity);
        this.capacity=capacity;
    }
    
    public int get(int key) {

            if(linkedHashMap.containsKey(key)){
                int value=linkedHashMap.get(key);
                linkedHashMap.remove(key);
                linkedHashMap.put(key, value);
                return value;
            }
            return -1;
        
    }
    
    public void set(int key, int value) {
              if(linkedHashMap.containsKey(key)){
                     linkedHashMap.remove(key);
                 }
                 else if(linkedHashMap.size()>=capacity){
                     
                          linkedHashMap.remove(linkedHashMap.keySet().iterator().next());
                  }
                  linkedHashMap.put(key, value);
       
    }
   

}