תשע שאלה 4

import java.util.*;
import java.util.Map.Entry;

public class Program {
    public static <T> HashMap<T, Collection<Integer>> createIndexMap(
            Collection<T> c) {
        HashMap<T, Collection<Integer>> m = new HashMap<T, Collection<Integer>>();

        int i = 0;
        for (T x : c) {
            if (m.containsKey(x)) {
                Collection<Integer> ci = m.get(x);
                ci.add(i);
            } else {
                Collection<Integer> ci = new Vector<Integer>();
                ci.add(i);
                m.put(x, ci);
            }
            i++;
        }
        return m;
    }

    public static void main(String[] args) {

        List<Integer> l = new LinkedList<Integer>();
        l.add(2);
        l.add(5);
        l.add(2);
        l.add(2);
        l.add(8);
        l.add(7);
        l.add(5);
        l.add(7);
        HashMap<Integer, Collection<Integer>> m = createIndexMap(l);

        for (Integer x : m.keySet()) {
            System.out.print(x + ":");
            for (Integer y : m.get(x))
                System.out.print(y + " ");
            System.out.println();

        }


        List<Point>  ll = new LinkedList<Point>();
        ll.add(new Point(2,1));
        ll.add(new Point(3,1));
        ll.add(new Point(2,1));
        ll.add(new Point(4,1));
        ll.add(new Point(3,1));
        ll.add(new Point(2,1));
        ll.add(new Point(2,1));
        ll.add(new Point(4,1));

        HashMap<Point, Collection<Integer>> mm = createIndexMap(ll);

        for (Point x : mm.keySet()) {
            System.out.print(x + ":");
            for (Integer y : mm.get(x))
                System.out.print(y + " ");
            System.out.println();

        }



    }
}