PQ(not implementet).java

public class PQ<Key extends Comparable<Key>>{
	private Key[] pq;
	private int N = 0;
	
	public PQ(int maxN){
		pq = (Key[]) new Comparable[maxN+1];
	}
	
	public boolean isEmpty(){
		return N == 0;
	}
	
	public int size(){
		return N;
	}
	
	public void add(Key v){
		pq[++N] = v;
		swim(N);
	}
	
	public Key poll(){
		Key max = pq[1];
		exch(1, N--);
		pq[N+1] = null;
		sink(1);
		return max;
	}
	
	
	private boolean less(int i, int j){
		return pq[i].compareTo(pq[j]) < 0;
	}
	private void exch(int i, int j){
		Key t = pq[i]; pq[i] = pq[j]; pq[j] = t;
	}
	private void swim(int k){
		while(k > 1 && less(k/2, k)){
			exch(k/2, k);
			k = k/2;
		}
	}
	private void sink(int k){	
		while(2*k <= N){
			int j = 2*k;
			if( j < N && less(j, j++)) j++;
			if(!less(k,j)) break;
			exch(k,j);
			k = j;
		}
	}
	
	
}