Add Compression Algorithm

Compression/src/genericheap.java

@@ -0,0 +1,93 @@
+
+
+import java.util.ArrayList;
+import java.util.Comparator;
+
+public class genericheap<T> {
+
+	private ArrayList<T> data = new ArrayList<>();
+	private Comparator<T> ctor;
+
+	public genericheap(Comparator<T> ctor) {
+		this.ctor=ctor;
+	}	
+
+	public int size() {
+		return data.size();
+	}
+
+	public boolean isEmpty() {
+		return data.isEmpty();
+	}
+
+	public void display() {
+		System.out.println(this.data);
+	}
+
+	public void add(T integer) {
+		data.add(integer);
+		upheapify(data.size() - 1);
+	}
+
+	private void upheapify(int ci) {
+		if (ci == 0) {
+			return;
+		}
+		int pi = (ci - 1) / 2;
+		if (isLarger(ci,pi) == true) {
+			swap(ci, pi);
+			upheapify(pi);
+		}
+	}
+
+	private boolean isLarger(int i, int j) {
+		T ith = data.get(i);
+		T jth = data.get(j);
+		if(ctor.compare(ith,jth)>0)
+		{
+			return true;
+		}
+		else
+		{
+			return false;
+		}
+	}
+
+	private void swap(int ci, int pi) {
+		T ith = data.get(ci);
+		T jth=data.get(pi);
+		data.set(ci, jth);
+		data.set(pi, ith);
+	}
+
+	public T getHP() {
+		return data.get(0);
+	}
+
+	public T removeHP() {
+	
+		swap(0, data.size() - 1);
+		T rv=data.remove(data.size()-1);
+		downheapify(0);
+		return rv;
+	}
+
+	private void downheapify(int pi) {
+		int lci = 2 * pi + 1;
+		int rci = 2 * pi + 2;
+
+		int max = pi;
+
+		if (lci < data.size() && isLarger(lci, max) == true) {
+			max = lci;
+		}
+		if (rci < data.size() && isLarger(rci, max) == true) {
+			max = rci;
+		}
+		if (max != pi) {
+			swap(pi, max);
+			downheapify(max);
+		}
+	}
+
+}