leetcode146.java

import java.util.*;

public class LRUCache {
    LinkedHashMap<Integer, Integer> cache;
    
    public LRUCache(int capacity) {
        cache = new LinkedHashMap<Integer, Integer>(){
            @Override
            protected boolean removeEldestEntry(Map.Entry<Integer, Integer> eldest){
            if(cache.size() > capacity)
                return true;
            return false;
            }
        };
        

    }
    
    public int get(int key) {
        if(cache.containsKey(key)){
            int value = cache.get(key);
            moveToFront(key);
            return value;
        }
        return -1;
    }
    
    public void set(int key, int value) {
        cache.put(key, value);
        moveToFront(key);
    }
    
    private void moveToFront(int key){
        int value = cache.get(key);
        cache.remove(key);
        cache.put(key, value);
    }
}