public class HashTable {

	private Node[] buckets;
        private static int BUCKETS;

	private class Node {
		int data;
		Node next;

		private Node(int item) {
			data = item;
			next = null;
		}
	}

	public HashTable(int numBuckets) {
		BUCKETS = numBuckets;
		buckets = new Node[BUCKETS];
	}

	public static int hashValue(int item) {
		if ( item < 0 )
			item = -item;
		return (item % BUCKETS);
	}

	public void add(int item) {
		int h;
		Node n;

		h = hashValue(item);
		n = new Node(item);
		n.next = buckets[h];
		buckets[h] = n;
	}

	public boolean contains(int item) {
		int h;
		Node p;

		h = hashValue(item);
		p = buckets[h];
		while ( p != null ) {
			if ( p.data == item )
				return true;
			p = p.next;
		}

		return false;
	}

	public boolean remove(int item) {
		int h;
		Node cur, back=null;

		h = hashValue(item);
		cur = buckets[h];
		while ( cur != null ) {
			if (cur.data == item) {
				if ( back == null )
					buckets[h] = cur.next;
				else
					back.next = cur.next;
				return true;
			}
			back = cur;
			cur = cur.next;
		}
		return false;
	}

	public void rehash(int numBuckets) {
		int h;
		Node [] newtable = new Node[numBuckets];

		for (Node p : buckets) {
			while (p != null) {
				h = p.data % numBuckets;
				Node n = new Node(p.data);
				n.next = newtable[h];
				newtable[h] = n;
				p = p.next;
			}
		}
		buckets = newtable;
		BUCKETS = numBuckets;
	}
}