用Java实现一个简单的二叉树

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import java.util.ArrayList;import java.util.Iterator;import java.util.List;/** * 一个简单二叉树结构 * @author tang * */public class Tree {    private Node    root;    public void add(Node node) {        if (root == null) {            root = node;        } else {            Node temp = root;            while (true) {                if (node.getValue() <= temp.getValue()) {// 往左找                    if (temp.getLeft() != null) {                        temp = temp.getLeft();                    } else {// 找到了                        temp.setLeft(node);                        node.setParent(temp);                        break;                    }                } else {// 往右找                    if (temp.getRight() != null) {                        temp = temp.getRight();                    } else {// 找到了                        temp.setRight(node);                        node.setParent(temp);                        break;                    }                }            }        }    }    public boolean remove(Node node) {        Node find = find(root, node);        if (find != null) {            Node parent = find.getParent();            if (parent == null) {// 如果要删除的节点是根节点                Node left = find.getLeft();                left.setParent(null);                root=left;                Node right = find.getRight();                Node leftMaxNode = getMaxNode(left);                leftMaxNode.setRight(right);                right.setParent(leftMaxNode);            } else if (parent.getLeft() == find) {// 如果要删除的节点在父节点的左侧                Node left = find.getLeft();                left.setParent(parent);                parent.setLeft(left);                Node right = find.getRight();                Node leftMaxNode = getMaxNode(left);                leftMaxNode.setRight(right);                right.setParent(leftMaxNode);            } else {// 如果要删除的节点在父节点的右侧                Node right = find.getRight();                right.setParent(parent);                parent.setRight(right);                Node left = find.getLeft();                Node rightMinNode = getMinNode(right);                rightMinNode.setLeft(left);                left.setParent(rightMinNode);            }            find.setLeft(null);            find.setRight(null);            find.setParent(null);            return true;        }        return false;    }    private Node getMinNode(Node node) {        Node min = node;        if (min != null) {            while (min.getLeft() != null) {                min = min.getLeft();            }        }        return min;    }    private Node getMaxNode(Node node) {        Node max = node;        if (max != null) {            while (max.getRight() != null) {                max = max.getRight();            }        }        return max;    }    private Node find(Node node, Node target) {        if (node == target) {            return node;        } else {            Node left = node.getLeft();            if (left != null) {                return find(left, target);            }            Node right = node.getRight();            if (right != null) {                return find(right, target);            }            return null;        }    }    public boolean contains(Node node) {        Node find = find(root, node);        if (find == null) {            return false;        } else {            return true;        }    }    private void toList(List<Node> list, Node node) {        if (node != null) {            Node left = node.getLeft();            if (left != null) {                toList(list, left);            }            list.add(node);            Node right = node.getRight();            if (right != null) {                toList(list, right);            }        }    }    private List<Node> toList() {        List<Node> list = new ArrayList<>();        toList(list, root);        return list;    }    public Iterator<Node> iterator() {        return toList().iterator();    }    public int size() {        return toList().size();    }    @Override    public String toString() {        return toList().toString();    }    public static void main(String[] args) {        Tree tree = new Tree();        List<Node> list = new ArrayList<>();        list.add(new Node(10));        list.add(new Node(5));        list.add(new Node(15));        list.add(new Node(3));        list.add(new Node(8));        list.add(new Node(12));        list.add(new Node(20));        list.add(new Node(1));        list.add(new Node(4));        list.add(new Node(6));        list.add(new Node(9));        list.add(new Node(11));        list.add(new Node(13));        list.add(new Node(16));        list.add(new Node(20));        for (Node treeNode : list) {            tree.add(treeNode);        }        System.out.println(tree);        tree.remove(list.get(1));        tree.remove(list.get(0));        System.out.println(tree);    }    /**     * 二叉树节点     * @author tang     */    public static class Node {        private Node    parent;        private Node    left;        private Integer     value;        private Node    right;        public Node(Integer value) {            this.value = value;        }        public Node getParent() {            return parent;        }        public void setParent(Node parent) {            this.parent = parent;        }        public Node getLeft() {            return left;        }        public void setLeft(Node left) {            this.left = left;        }        public Integer getValue() {            return value;        }        public Node getRight() {            return right;        }        public void setRight(Node right) {            this.right = right;        }        @Override        public int hashCode() {            final int prime = 31;            int result = 1;            result = prime * result + ((value == null) ? 0 : value.hashCode());            return result;        }        @Override        public boolean equals(Object obj) {            if (this == obj)                return true;            if (obj == null)                return false;            if (getClass() != obj.getClass())                return false;            Node other = (Node) obj;            if (value == null) {                if (other.value != null)                    return false;            } else                if (!value.equals(other.value))                    return false;            return true;        }        @Override        public String toString() {            return value.toString();        }    }}
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