4.13

LRU算法Java实现

public class LRUCache {
private LinkedHashMap map;
private int capacity;
public LRUCache(int capacity){
this.capacity = capacity;
map = new LinkedHashMap<>();
}
public int get(int key){
Integer value = map.get(key);
if(map.get(key)==null){
value = -1;
}
else{
map.put(key,map.remove(key));
}
return value;
}
public void put(int key,int value)
{
if(map.containsKey(key)){
map.remove(key);
}
map.put(key,value);
if(map.size()>capacity){
Iterator iterator = map.keySet().iterator();
Integer next = iterator.next();
map.remove(next);
}
}

**public static void **main(String[] args) {<br />        LRUCache cache = **new **LRUCache(2 );
    cache.put(2, 1);<br />        cache.put(1, 1);<br />        cache.put(2, 3);_//作废2=1<br />        _cache.put(4, 1);_//作废1=1
    _System.**_out_**.println(cache.get(1));_//-1<br />        _System.**_out_**.println(cache.get(2));_//3<br />    _}<br />}