二叉树的基本操作

定义简单的树

 

package tree;
/** *//**
 * 二叉树的定义类
 * @author root
 *
 */
public class BinarySearchTree ...{

    /** *//**
     * 存储的值
     */
    protected int key;
    /** *//**
     * 左节点
     */
    protected BinarySearchTree left;
    /** *//**
     * 右节点
     */
    protected BinarySearchTree right;
    
    public BinarySearchTree()...{
        this.left = this.right = null;
    }
    public BinarySearchTree(int key)...{
        this(key,null,null);
    }
    public BinarySearchTree(int key,BinarySearchTree left,BinarySearchTree right)...{
        this.key = key;
        this.left = left;
        this.right = right;
    }
}

遍历树，广度优先遍历

 

/** *//**
 * 广度优先遍历二叉树
 * 
 * @author root
 * 
 */
public class BreadthFirstTraversal ...{

    /** *//**
     * 广度优先遍历:(此方法的为由上到下,由左到右遍历) 张磊 2007-6-7
     * 
     * @param bin
     */
    public List<Integer> traversal(BinarySearchTree bin) ...{
        // java.util.concurrent允许多线程修改
        ArrayBlockingQueue<BinarySearchTree> au = new ArrayBlockingQueue<BinarySearchTree>(
                1024, true);
        if (bin != null)
            au.offer(bin);
        List<Integer> list = new ArrayList<Integer>();
        BinarySearchTree bina = null;
        while (!au.isEmpty()) ...{
            bina = (BinarySearchTree) au.poll();
            list.add(bina.key);
            if (bina.left != null) ...{
                au.offer(bina.left);
            }
            if (bina.right != null) ...{
                au.offer(bina.right);
            }
        }

        return list;
    }

    public static void main(String[] args) ...{
        /**//*
         * 验证广度优先遍历
         *       13
         *      /   
         *    10    25
         *   /      /  
         *  2   12 20  31
         *            /
         *           29
         */
        BinarySearchTree tree = new BinarySearchTree(13, new BinarySearchTree(
                10, new BinarySearchTree(2, null, null), new BinarySearchTree(
                        12, null, null)), new BinarySearchTree(25,
                new BinarySearchTree(20, null, null), new BinarySearchTree(31,
                        new BinarySearchTree(29, null, null), null)));
        BreadthFirstTraversal b = new BreadthFirstTraversal();
        List<Integer> list = b.traversal(tree);
        Iterator it = list.iterator();
        while(it.hasNext())...{
            System.out.println(it.next());
        }
    }

 

归并法删除节点

 

package tree;
/** *//**
 * 归并删除节点的类
 * @author root
 *
 */
public class DeleteByMerging ...{

    /** *//**
     * 归并删除节点的方法
     * 张磊
     *2007-6-11
     *@param key
     *@param tree
     *@return
     */
    public BinarySearchTree deleteByMerging(int key,BinarySearchTree tree)...{
        //先找到key对应的节点
        BinarySearchTree p = tree;
        while(p != null && p.key != key)...{
            if(key > p.key)
                p = p.right;
            else
                p = p.left;
        }
        //寻找此节点的左子树的最右节点
        
        return tree;
    }
}

 

插入新节点

 

package tree;
/** *//**
 * 向二叉树插入新节点
 * @author root
 *
 */
public class InsertNewNode ...{

    /** *//**
     * 向二叉树插入新节点
     * 张磊
     *2007-6-11
     *@param key
     *@param tree
     *@return
     */
    public BinarySearchTree insertNode(int key,BinarySearchTree tree)...{
        //找到适合它的空节点
        while(tree != null)...{
            if(key > tree.key)
                tree = tree.right;
            else
                tree = tree.left;
        }
        //判断在这个空节点上新节点插入到左右哪个分支
        BinarySearchTree p = new BinarySearchTree(key);
        if(key>tree.key)
            tree.left = p;
        else
            tree.right = p;
        
        return tree;
    }
}

 

简单的二叉树搜索

 

package tree;
/** *//**
 * 二叉查找树的简单搜索算法--简单的思路
 * @author root
 *
 */
public class SearchTree ...{

    public BinarySearchTree search(BinarySearchTree node,int key)...{
        while(node != null)...{
            if(key == node.key)...{
                return node;
            }else if(key<node.key)...{
                node = node.left;
            }else...{
                node = node.right;
            }
        }
        return null;
    }
}