BitSet are added

Test.java

import java.util.* ;

class Node {
      public int data;
      public Node next;
      public Node(int data, Node next) {
         this.data = data; this.next = next;
      }
}

class LongIntParallelHashMultimap {
      Node[] l ;
      BitSet bits = new BitSet(Integer.MAX_VALUE);
      public LongIntParallelHashMultimap() {
         l = new Node[Integer.MAX_VALUE];
      }

      public void load(){
      }
      public void put(int key, int value) {
      	bits.set(key , true) ; //bitset to find which linked list are filled up
        // Assume ordering is significant, for now.
        Node prev = l[key];
        if (prev == null) {
           l[key] = new Node(value, null);
        } else {
           while (prev.next != null) {
             prev = prev.next;
           }
           prev.next = new Node(value, null);
        }
     }
     public int[] get(int key) {
       // Re-counting the values every time is...probably actually better than storing the counts.
       // Based on the listed RAM constraints, we almost certainly cannot afford the overhead of
       // the LinkedList objects.
       // Anyway, with an average count around 3, this shouldn't be a significant hit.
       int count = 0;
       for (Node n = l[key]; n != null; n = n.next) {
          count++;
       }
       int[] result = new int[count];
       int i = 0;
       for (Node n = l[key]; n != null; n = n.next) {
         result[i++] = n.data;
       }
       return result;
     }
     public void save() {
 }
}


public class Test{
public static void main(String args[]) {
    try {

long startTime = System.nanoTime();
LongIntParallelHashMultimap lph = new LongIntParallelHashMultimap();
long endTime = System.nanoTime() - startTime;
System.out.println(endTime);
startTime = System.nanoTime();
for (int i= 0 ; i < 2500000 ; i++)
lph.put(i, i+100);
endTime = System.nanoTime() - startTime;
System.out.println(endTime);
startTime = System.nanoTime();

startTime = System.nanoTime();
for (int i= 0 ; i < 100 ; i++){
int k[] = lph.get(i);
System.out.print(k[0] + "  ");
}
endTime = System.nanoTime() - startTime;
      System.out.println(endTime);
      startTime = System.nanoTime();

    } catch (Exception e) {
        System.err.println("Error: " + e.getMessage());
    }
}
}