package testUtility;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.Vector;
import java.util.Map.Entry;

public class test_condense
{
  public static void main(String[] args) 
  {
    HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
    HashMap<Integer,Vector<Integer>> revert = new HashMap<Integer,Vector<Integer>>();
    map.put(4, 2);
    map.put(5, 2);
    map.put(1, 6);
    map.put(3, 6);
    map.put(7, 1);
    Set<Entry<Integer, Integer>> set = map.entrySet();
    Iterator<Entry<Integer, Integer>> itor = set.iterator();
    while(itor.hasNext())
    {
      Entry<Integer, Integer> entry = itor.next();
      int NumberwithOccurance = entry.getKey();
      int Occurance = entry.getValue();
      if( revert.containsKey(entry.getValue()) == false)
      {
        Vector<Integer> NumberListWithSameOccurance = new Vector<Integer>();  
        NumberListWithSameOccurance.add(NumberwithOccurance);
        revert.put(Occurance, NumberListWithSameOccurance);
      }
      else
      {
        Vector<Integer> existingNumberList = revert.get(Occurance);
        existingNumberList.add(NumberwithOccurance);
        revert.put(Occurance, existingNumberList);
      }
    }
    Set<Entry<Integer, Vector<Integer>>> Revertset = revert.entrySet();
    Iterator<Entry<Integer, Vector<Integer>>> Revertitor = Revertset.iterator();
    while(Revertitor.hasNext())
    {
      Entry<Integer, Vector<Integer>> entry = Revertitor.next();
      System.out.println("Occruance: " + entry.getKey());
      for( int i = 0 ; i < entry.getValue().size(); i ++)
      {
        System.out.println("Number with same Occurance: " + entry.getValue().elementAt(i));
      }
    }
    
  }
}