Thread: Creating and Using a Heap. Index out of Bounds

Hey guys, I'm currently trying to build and use a heap so I created the two following classes.

import java.util.*;
 
public class MyHeap<E extends Comparable<E>>
{
  private int size = 0;
  private ArrayList<E> heap = new ArrayList<E>();
  public void add(E data)
  {
    heap.add(size, data);
    size++;
    reheapup(size-1);
  }
 
  public E remove()
  {
    E temp = heap.get(0);
    heap.set(0, heap.get(size-1));
    size--;
    reheapDown(0);
    return temp;
  }
 
  private void reheapup(int n)
  {
    if(n==0) return;
    E curr = heap.get(n);
    E parent = heap.get((n-1)/2);
    if (curr.compareTo(parent) > 0) return;
    heap.set(n, parent);
    heap.set((n-1)/2, curr);
    reheapup((n-1)/2);
  }
 
  private void reheapDown(int n)
  {
    if (n >= size) return;
    if (2*n+2 < size)
    {
      E curr = heap.get(n);
      E left = heap.get(2*n+1);
      E right = heap.get(2*n+2);
      if (curr.compareTo(left) > 0 || curr.compareTo(right) > 0)
      {
        if(left.compareTo(right) < 0)
        {
          heap.set(n, left);
          heap.set(2*n+1, curr);
          reheapDown(2*n+1);
        }
        else
        {
          heap.set(n, right);
          heap.set(2*n+2, curr);
          reheapDown(2*n+2);
        }
      }
    }
    else
    {
      E curr = heap.get(n);
      E left = heap.get(2*n+1);
      if(curr.compareTo(left) > 0)
      {
        heap.set(n,  left);
        heap.set(2*n+1, curr);
      }
    }
  }
}

public class DriverP07 
{
  public static void main(String[] args)
  {
    MyHeap stringHeap = new MyHeap();
    MyHeap integerHeap = new MyHeap();
    //int temp;
    //String s;
    integerHeap.add(1);
    integerHeap.add(2);
    integerHeap.add(3);
    integerHeap.add(4);
    integerHeap.add(5);
    integerHeap.add(6);
    integerHeap.add(7);
    integerHeap.add(8);
    integerHeap.add(9);
    integerHeap.add(10);
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    integerHeap.remove();
    stringHeap.add("A");
    stringHeap.add("B");
    stringHeap.add("C");
    stringHeap.add("D");
    stringHeap.add("E");
    stringHeap.add("F");
    stringHeap.add("G");
    stringHeap.add("H");
    stringHeap.add("I");
    stringHeap.add("J");
    stringHeap.add("K");
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    stringHeap.remove();
    System.out.println("finished");
  }
}

when I run my program I get an index out of bounds errors or more specifically.

java.lang.IndexOutOfBoundsException: Index: 15, Size: 10
at java.util.ArrayList.rangeCheck(ArrayList.java:604)
at java.util.ArrayList.get(ArrayList.java:382)
at MyHeap.reheapDown(MyHeap.java:61)
at MyHeap.reheapDown(MyHeap.java:48)
at MyHeap.reheapDown(MyHeap.java:48)
at MyHeap.reheapDown(MyHeap.java:48)
at MyHeap.remove(MyHeap.java:19)
at DriverP07.main(DriverP07.java:19)


So, I'm assuming the error is really simple to fix, but I have no idea how to fix it. Any help would be appreciated.