Java 实现二叉树

原文链接:

http://www.cnblogs.com/lzq198754/p/5857597.html

public class TreeNode {
    private TreeNode leftNode;
    private TreeNode rightNode;
    private int value;
    private boolean isdeleteOrNot;

    public TreeNode getLeftNode() {
        return leftNode;
    }

    public void setLeftNode(TreeNode leftNode) {
        this.leftNode = leftNode;
    }

    public TreeNode getRightNode() {
        return rightNode;
    }

    public TreeNode() {
        super();
    }

    public void setRightNode(TreeNode rightNode) {
        this.rightNode = rightNode;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public boolean isIsdeleteOrNot() {
        return isdeleteOrNot;
    }

    public void setIsdeleteOrNot(boolean isdeleteOrNot) {
        this.isdeleteOrNot = isdeleteOrNot;
    }

    public TreeNode(int value) {
        this(null, null, value, false);
    }

    public TreeNode(TreeNode leftNode, TreeNode rightNode, int value, boolean isdeleteOrNot) {
        super();
        this.leftNode = leftNode;
        this.rightNode = rightNode;
        this.value = value;
        this.isdeleteOrNot = isdeleteOrNot;
    }

}

/**
 * 二叉树的 Java 实现
 * 
 */
public class BinTree {
    private TreeNode rootNode;

    public TreeNode getRootNode() {
        return rootNode;
    }

    /**
     * 二叉树的插入操作
     */
    public void insertValue(int value) {
        TreeNode newNode = new TreeNode(value);
        // 如果根节点为空, 则新节点即是根节点
        if (rootNode == null) {
            rootNode = newNode;
            rootNode.setLeftNode(null);
            rootNode.setRightNode(null);
        } else {
            TreeNode currenNode = rootNode;
            TreeNode parenNode;
            while (true) {
                parenNode = currenNode;
                // 放在右边
                if (newNode.getValue() > currenNode.getValue()) {
                    currenNode = currenNode.getRightNode();
                    if (currenNode == null) {
                        parenNode.setRightNode(newNode);
                        return;
                    }
                } else {
                    // 放在左边
                    currenNode = currenNode.getLeftNode();
                    if (currenNode == null) {
                        parenNode.setLeftNode(newNode);
                        return;
                    }

                }
            }
        }
    }

    /**
     * 二叉树的升序遍历
     */
    public void orderByAsc(TreeNode treeNode) {
        if (treeNode != null && treeNode.isIsdeleteOrNot() == false) {
            orderByAsc(treeNode.getLeftNode());
            System.out.println(treeNode.getValue());
            orderByAsc(treeNode.getRightNode());
        }
    }

    /**
     * 二叉树的降序遍历
     */
    public void orderByDesc(TreeNode treeNode) {
        if (treeNode != null && treeNode.isIsdeleteOrNot() == false) {
            orderByDesc(treeNode.getRightNode());
            System.out.println(treeNode.getValue());
            orderByDesc(treeNode.getLeftNode());
        }
    }

    /**
     * 二叉树的查找
     */
    public TreeNode findKey(int key) {
        TreeNode currenNode = rootNode;
        if (currenNode != null) {
            while (currenNode.getValue() != key) {
                if (currenNode.getValue() > key) {
                    currenNode = currenNode.getLeftNode();
                } else {
                    currenNode = currenNode.getRightNode();
                }
                if (currenNode == null) {
                    return null;
                }
            }
            if (currenNode.isIsdeleteOrNot()) {
                return null;
            } else {
                return currenNode;
            }
        } else {
            return null;
        }
    }

    public static void main(String[] args) {
        BinTree binTree = new BinTree();
        binTree.insertValue(10);
        binTree.insertValue(12);
        binTree.insertValue(13);
        binTree.orderByAsc(binTree.getRootNode());
        System.out.println("-------------------");
        binTree.orderByDesc(binTree.getRootNode());
        System.out.println("-------------------");
        System.out.println(binTree.findKey(10));
    }

}