Question

How can we implement an LRU cache using just a single container i.e. map or unordered_map?

Expected operations:
1. find(key_t) - find a certain value in cache
2. insert(key_t, value_t) - insert a new value to the cache

Answer 1

impletement LRU class which extends LinkedHashMap and override removeEldestEntry like this:

class LRULinkedHashMap<K,V> extends LinkedHashMap<K,V>{  
    private int capacity;  

    LRULinkedHashMap(int capacity){  
        super(16,0.75f,true);  
        this.capacity=capacity;  
    }  

    @Override  
    protected boolean removeEldestEntry(Map.Entry<K, V> eldest){   
        return size() > capacity;  
    }    
}

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