2017-05-05 40 views
-1

给定一个平衡的二叉树,我必须找到所有节点的总和。 该计划的源代码将高度赞赏。 它可以是在JAVA,C或C++ Discription On the Image查找树的总和

回答

1

这是从Java的Oracle的TreeSet的,你可以看它,学习它,了解它。我不知道是谁都会想再次编写本,或多一次...做所有的工作,也许如果你先尝试一点点,分享你的进步,有人会帮助你解决你的错误

public class TreeSet<E> extends AbstractSet<E> 
    implements NavigableSet<E>, Cloneable, java.io.Serializable 
{ 
    /** 
    * The backing map. 
    */ 
    private transient NavigableMap<E,Object> m; 

    // Dummy value to associate with an Object in the backing Map 
    private static final Object PRESENT = new Object(); 

    /** 
    * Constructs a set backed by the specified navigable map. 
    */ 
    TreeSet(NavigableMap<E,Object> m) { 
     this.m = m; 
    } 

    /** 
    * Constructs a new, empty tree set, sorted according to the 
    * natural ordering of its elements. All elements inserted into 
    * the set must implement the {@link Comparable} interface. 
    * Furthermore, all such elements must be <i>mutually 
    * comparable</i>: {@code e1.compareTo(e2)} must not throw a 
    * {@code ClassCastException} for any elements {@code e1} and 
    * {@code e2} in the set. If the user attempts to add an element 
    * to the set that violates this constraint (for example, the user 
    * attempts to add a string element to a set whose elements are 
    * integers), the {@code add} call will throw a 
    * {@code ClassCastException}. 
    */ 
    public TreeSet() { 
     this(new TreeMap<E,Object>()); 
    } 

    /** 
    * Constructs a new, empty tree set, sorted according to the specified 
    * comparator. All elements inserted into the set must be <i>mutually 
    * comparable</i> by the specified comparator: {@code comparator.compare(e1, 
    * e2)} must not throw a {@code ClassCastException} for any elements 
    * {@code e1} and {@code e2} in the set. If the user attempts to add 
    * an element to the set that violates this constraint, the 
    * {@code add} call will throw a {@code ClassCastException}. 
    * 
    * @param comparator the comparator that will be used to order this set. 
    *  If {@code null}, the {@linkplain Comparable natural 
    *  ordering} of the elements will be used. 
    */ 
    public TreeSet(Comparator<? super E> comparator) { 
     this(new TreeMap<>(comparator)); 
    } 

    /** 
    * Constructs a new tree set containing the elements in the specified 
    * collection, sorted according to the <i>natural ordering</i> of its 
    * elements. All elements inserted into the set must implement the 
    * {@link Comparable} interface. Furthermore, all such elements must be 
    * <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a 
    * {@code ClassCastException} for any elements {@code e1} and 
    * {@code e2} in the set. 
    * 
    * @param c collection whose elements will comprise the new set 
    * @throws ClassCastException if the elements in {@code c} are 
    *   not {@link Comparable}, or are not mutually comparable 
    * @throws NullPointerException if the specified collection is null 
    */ 
    public TreeSet(Collection<? extends E> c) { 
     this(); 
     addAll(c); 
    } 

    /** 
    * Constructs a new tree set containing the same elements and 
    * using the same ordering as the specified sorted set. 
    * 
    * @param s sorted set whose elements will comprise the new set 
    * @throws NullPointerException if the specified sorted set is null 
    */ 
    public TreeSet(SortedSet<E> s) { 
     this(s.comparator()); 
     addAll(s); 
    } 

    /** 
    * Returns an iterator over the elements in this set in ascending order. 
    * 
    * @return an iterator over the elements in this set in ascending order 
    */ 
    public Iterator<E> iterator() { 
     return m.navigableKeySet().iterator(); 
    } 

    /** 
    * Returns an iterator over the elements in this set in descending order. 
    * 
    * @return an iterator over the elements in this set in descending order 
    * @since 1.6 
    */ 
    public Iterator<E> descendingIterator() { 
     return m.descendingKeySet().iterator(); 
    } 

    /** 
    * @since 1.6 
    */ 
    public NavigableSet<E> descendingSet() { 
     return new TreeSet<>(m.descendingMap()); 
    } 

    /** 
    * Returns the number of elements in this set (its cardinality). 
    * 
    * @return the number of elements in this set (its cardinality) 
    */ 
    public int size() { 
     return m.size(); 
    } 

    /** 
    * Returns {@code true} if this set contains no elements. 
    * 
    * @return {@code true} if this set contains no elements 
    */ 
    public boolean isEmpty() { 
     return m.isEmpty(); 
    } 

    /** 
    * Returns {@code true} if this set contains the specified element. 
    * More formally, returns {@code true} if and only if this set 
    * contains an element {@code e} such that 
    * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>. 
    * 
    * @param o object to be checked for containment in this set 
    * @return {@code true} if this set contains the specified element 
    * @throws ClassCastException if the specified object cannot be compared 
    *   with the elements currently in the set 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    */ 
    public boolean contains(Object o) { 
     return m.containsKey(o); 
    } 

    /** 
    * Adds the specified element to this set if it is not already present. 
    * More formally, adds the specified element {@code e} to this set if 
    * the set contains no element {@code e2} such that 
    * <tt>(e==null&nbsp;?&nbsp;e2==null&nbsp;:&nbsp;e.equals(e2))</tt>. 
    * If this set already contains the element, the call leaves the set 
    * unchanged and returns {@code false}. 
    * 
    * @param e element to be added to this set 
    * @return {@code true} if this set did not already contain the specified 
    *   element 
    * @throws ClassCastException if the specified object cannot be compared 
    *   with the elements currently in this set 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    */ 
    public boolean add(E e) { 
     return m.put(e, PRESENT)==null; 
    } 

    /** 
    * Removes the specified element from this set if it is present. 
    * More formally, removes an element {@code e} such that 
    * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>, 
    * if this set contains such an element. Returns {@code true} if 
    * this set contained the element (or equivalently, if this set 
    * changed as a result of the call). (This set will not contain the 
    * element once the call returns.) 
    * 
    * @param o object to be removed from this set, if present 
    * @return {@code true} if this set contained the specified element 
    * @throws ClassCastException if the specified object cannot be compared 
    *   with the elements currently in this set 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    */ 
    public boolean remove(Object o) { 
     return m.remove(o)==PRESENT; 
    } 

    /** 
    * Removes all of the elements from this set. 
    * The set will be empty after this call returns. 
    */ 
    public void clear() { 
     m.clear(); 
    } 

    /** 
    * Adds all of the elements in the specified collection to this set. 
    * 
    * @param c collection containing elements to be added to this set 
    * @return {@code true} if this set changed as a result of the call 
    * @throws ClassCastException if the elements provided cannot be compared 
    *   with the elements currently in the set 
    * @throws NullPointerException if the specified collection is null or 
    *   if any element is null and this set uses natural ordering, or 
    *   its comparator does not permit null elements 
    */ 
    public boolean addAll(Collection<? extends E> c) { 
     // Use linear-time version if applicable 
     if (m.size()==0 && c.size() > 0 && 
      c instanceof SortedSet && 
      m instanceof TreeMap) { 
      SortedSet<? extends E> set = (SortedSet<? extends E>) c; 
      TreeMap<E,Object> map = (TreeMap<E, Object>) m; 
      Comparator<? super E> cc = (Comparator<? super E>) set.comparator(); 
      Comparator<? super E> mc = map.comparator(); 
      if (cc==mc || (cc != null && cc.equals(mc))) { 
       map.addAllForTreeSet(set, PRESENT); 
       return true; 
      } 
     } 
     return super.addAll(c); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code fromElement} or {@code toElement} 
    *   is null and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    * @since 1.6 
    */ 
    public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, 
            E toElement, boolean toInclusive) { 
     return new TreeSet<>(m.subMap(fromElement, fromInclusive, 
             toElement, toInclusive)); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code toElement} is null and 
    *   this set uses natural ordering, or its comparator does 
    *   not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    * @since 1.6 
    */ 
    public NavigableSet<E> headSet(E toElement, boolean inclusive) { 
     return new TreeSet<>(m.headMap(toElement, inclusive)); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code fromElement} is null and 
    *   this set uses natural ordering, or its comparator does 
    *   not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    * @since 1.6 
    */ 
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) { 
     return new TreeSet<>(m.tailMap(fromElement, inclusive)); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code fromElement} or 
    *   {@code toElement} is null and this set uses natural ordering, 
    *   or its comparator does not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    */ 
    public SortedSet<E> subSet(E fromElement, E toElement) { 
     return subSet(fromElement, true, toElement, false); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code toElement} is null 
    *   and this set uses natural ordering, or its comparator does 
    *   not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    */ 
    public SortedSet<E> headSet(E toElement) { 
     return headSet(toElement, false); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if {@code fromElement} is null 
    *   and this set uses natural ordering, or its comparator does 
    *   not permit null elements 
    * @throws IllegalArgumentException {@inheritDoc} 
    */ 
    public SortedSet<E> tailSet(E fromElement) { 
     return tailSet(fromElement, true); 
    } 

    public Comparator<? super E> comparator() { 
     return m.comparator(); 
    } 

    /** 
    * @throws NoSuchElementException {@inheritDoc} 
    */ 
    public E first() { 
     return m.firstKey(); 
    } 

    /** 
    * @throws NoSuchElementException {@inheritDoc} 
    */ 
    public E last() { 
     return m.lastKey(); 
    } 

    // NavigableSet API methods 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    * @since 1.6 
    */ 
    public E lower(E e) { 
     return m.lowerKey(e); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    * @since 1.6 
    */ 
    public E floor(E e) { 
     return m.floorKey(e); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    * @since 1.6 
    */ 
    public E ceiling(E e) { 
     return m.ceilingKey(e); 
    } 

    /** 
    * @throws ClassCastException {@inheritDoc} 
    * @throws NullPointerException if the specified element is null 
    *   and this set uses natural ordering, or its comparator 
    *   does not permit null elements 
    * @since 1.6 
    */ 
    public E higher(E e) { 
     return m.higherKey(e); 
    } 

    /** 
    * @since 1.6 
    */ 
    public E pollFirst() { 
     Map.Entry<E,?> e = m.pollFirstEntry(); 
     return (e == null) ? null : e.getKey(); 
    } 

    /** 
    * @since 1.6 
    */ 
    public E pollLast() { 
     Map.Entry<E,?> e = m.pollLastEntry(); 
     return (e == null) ? null : e.getKey(); 
    } 

    /** 
    * Returns a shallow copy of this {@code TreeSet} instance. (The elements 
    * themselves are not cloned.) 
    * 
    * @return a shallow copy of this set 
    */ 
    public Object clone() { 
     TreeSet<E> clone = null; 
     try { 
      clone = (TreeSet<E>) super.clone(); 
     } catch (CloneNotSupportedException e) { 
      throw new InternalError(); 
     } 

     clone.m = new TreeMap<>(m); 
     return clone; 
    } 

    /** 
    * Save the state of the {@code TreeSet} instance to a stream (that is, 
    * serialize it). 
    * 
    * @serialData Emits the comparator used to order this set, or 
    *    {@code null} if it obeys its elements' natural ordering 
    *    (Object), followed by the size of the set (the number of 
    *    elements it contains) (int), followed by all of its 
    *    elements (each an Object) in order (as determined by the 
    *    set's Comparator, or by the elements' natural ordering if 
    *    the set has no Comparator). 
    */ 
    private void writeObject(java.io.ObjectOutputStream s) 
     throws java.io.IOException { 
     // Write out any hidden stuff 
     s.defaultWriteObject(); 

     // Write out Comparator 
     s.writeObject(m.comparator()); 

     // Write out size 
     s.writeInt(m.size()); 

     // Write out all elements in the proper order. 
     for (E e : m.keySet()) 
      s.writeObject(e); 
    } 

    /** 
    * Reconstitute the {@code TreeSet} instance from a stream (that is, 
    * deserialize it). 
    */ 
    private void readObject(java.io.ObjectInputStream s) 
     throws java.io.IOException, ClassNotFoundException { 
     // Read in any hidden stuff 
     s.defaultReadObject(); 

     // Read in Comparator 
     Comparator<? super E> c = (Comparator<? super E>) s.readObject(); 

     // Create backing TreeMap 
     TreeMap<E,Object> tm; 
     if (c==null) 
      tm = new TreeMap<>(); 
     else 
      tm = new TreeMap<>(c); 
     m = tm; 

     // Read in size 
     int size = s.readInt(); 

     tm.readTreeSet(size, s, PRESENT); 
    } 

    private static final long serialVersionUID = -2479143000061671589L; 
}