public class BinomialHeap<E> implements Cloneable {

        transient BinomialHeapEntry head; // 根表中的第一个元素

        int size;                         // 整个二项堆的大小（结点数）

        private class BinomialHeapEntry {

		E element;

		transient BinomialHeapEntry parent = null, child = null,

				sibling = null;

		transient int degree = 0;

                private BinomialHeapEntry(E element) {

			this.element = element;

		}

                // 获得孩子结点的迭代器

                private Iterable<BinomialHeapEntry> children {...}

        }

        @Override

	public BinomialHeap<E> clone() {

		// TODO Auto-generated method stub

		BinomialHeap<E> clone;

		try {

			clone = (BinomialHeap<E>) super.clone();

		} catch (CloneNotSupportedException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

			throw new InternalError();

		}

		BinomialHeapEntry newHead = null, curRoot = null;

                // 遍历根表

		Iterator<HeapEntry<E>> rootIt = this.roots().iterator();

		while(rootIt.hasNext()){

			BinomialHeapEntry root = (BinomialHeapEntry) rootIt.next();

                        // 拷贝根节点下的整棵二项树
                        // BUG引入的地方

			BinomialHeapEntry newRoot = cloneBinomialTree(root);

			if(curRoot == null){

				newHead = newRoot;

			} else {

				curRoot.sibling = newRoot;

			}

			curRoot = newRoot;

		}

		clone.head = newHead;

		return clone;

	}

        // 拷贝根节点（含根节点）下的整棵子树

	private BinomialHeapEntry cloneBinomialTree(BinomialHeapEntry root){

		BinomialHeapEntry newRoot = new BinomialHeapEntry(root.element());

		BinomialHeapEntry curChild = null;

                // 遍历根节点的所有孩子结点

		Iterator<HeapEntry<E>> childIt = root.children().iterator();

		while(childIt.hasNext()){

			BinomialHeapEntry child = (BinomialHeapEntry) childIt.next();

			// 递归拷贝孩子节点下的子树

                        BinomialHeapEntry newChild = cloneBinomialTree(child);

			newChild.parent = newRoot;

			if(curChild == null){

				newRoot.child = newChild;

			} else {

				curChild.sibling = newChild;

			}

			curChild = newChild;

		}

		newRoot.degree = root.degree;

		return newRoot;

	}

}