[Java][АПС] - Love for the Twins (GFG)

import java.util.Scanner;
import java.util.Hashtable;
import java.util.LinkedHashMap;

class CBHT<K extends Comparable<K>, E> {

	// An object of class CBHT is a closed-bucket hash table, containing
	// entries of class MapEntry.
	private SLLNode<MapEntry<K,E>>[] buckets;

	@SuppressWarnings("unchecked")
	public CBHT(int m) {
		// Construct an empty CBHT with m buckets.
		buckets = (SLLNode<MapEntry<K,E>>[]) new SLLNode[m];
	}

	private int hash(K key) {
		// Translate key to an index of the array buckets.
		return Math.abs(key.hashCode()) % buckets.length;
	}

	public SLLNode<MapEntry<K,E>> search(K targetKey) {
		// Find which if any node of this CBHT contains an entry whose key is
		// equal
		// to targetKey. Return a link to that node (or null if there is none).
		int b = hash(targetKey);
		for (SLLNode<MapEntry<K,E>> curr = buckets[b]; curr != null; curr = curr.succ) {
			if (targetKey.equals(((MapEntry<K, E>) curr.element).key))
				return curr;
		}
		return null;
	}

	public void insert(K key, E val) {		// Insert the entry <key, val> into this CBHT.
		MapEntry<K, E> newEntry = new MapEntry<K, E>(key, val);
		int b = hash(key);
		for (SLLNode<MapEntry<K,E>> curr = buckets[b]; curr != null; curr = curr.succ) {
			if (key.equals(((MapEntry<K, E>) curr.element).key)) {
				// Make newEntry replace the existing entry ...
				curr.element = newEntry;
				return;
			}
		}
		// Insert newEntry at the front of the 1WLL in bucket b ...
		buckets[b] = new SLLNode<MapEntry<K,E>>(newEntry, buckets[b]);
	}

	public void delete(K key) {
		// Delete the entry (if any) whose key is equal to key from this CBHT.
		int b = hash(key);
		for (SLLNode<MapEntry<K,E>> pred = null, curr = buckets[b]; curr != null; pred = curr, curr = curr.succ) {
			if (key.equals(((MapEntry<K,E>) curr.element).key)) {
				if (pred == null)
					buckets[b] = curr.succ;
				else
					pred.succ = curr.succ;
				return;
			}
		}
	}

	public String toString() {
		String temp = "";
		for (int i = 0; i < buckets.length; i++) {
			temp += i + ":";
			for (SLLNode<MapEntry<K,E>> curr = buckets[i]; curr != null; curr = curr.succ) {
				temp += curr.element.toString() + " ";
			}
			temp += "\n";
		}
		return temp;
	}

}
class SLLNode<E> {
	protected E element;
	protected SLLNode<E> succ;

	public SLLNode(E elem, SLLNode<E> succ) {
		this.element = elem;
		this.succ = succ;
	}

	@Override
	public String toString() {
		return element.toString();
	}
}
class MapEntry<K extends Comparable<K>,E> implements Comparable<K> {

    // Each MapEntry object is a pair consisting of a key (a Comparable
    // object) and a value (an arbitrary object).
    K key;
    E value;

    public MapEntry (K key, E val) {
        this.key = key;
        this.value = val;
    }

    public int compareTo (K that) {
    // Compare this map entry to that map entry.
        @SuppressWarnings("unchecked")
		MapEntry<K,E> other = (MapEntry<K,E>) that;
        return this.key.compareTo(other.key);
    }

    public String toString () {
        return "<" + key + "," + value + ">";
    }
}


public class GFG {

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		int zbir = 0;
		CBHT<Integer,Integer> hashtable = new CBHT<Integer,Integer>(300);
		for(int i=0;i<n;i++) {
			zbir = 0;
			int t = input.nextInt();
			for(int k=0;k<t;k++) {
				int prv = input.nextInt();
				SLLNode<MapEntry<Integer,Integer>> node = hashtable.search(prv);
				if(node!=null) {
					int val = node.element.value;
					hashtable.insert(node.element.key, ++val);
					if(node.element.value%2==0) {
						zbir+=2;
					}
				}
				else {
					hashtable.insert(prv,1);
				}

				}
				System.out.println(zbir);

			}
	}

}