AVL树

来源：互联网发布：cs扫描仪软件下载编辑：程序博客网时间：2024/05/19 02:31
package avl;/** * Created by long.chen  on 2017/12/21. * 平衡二叉树 */public class AVLTree<T extends Comparable<T>> {//泛型    private AVLTreeNode<T> root;//根节点    class AVLTreeNode<T extends Comparable<T>> {        T key;//键值        int height;//高度        AVLTreeNode<T> left;//左子树        AVLTreeNode<T> right;//右字树        public AVLTreeNode(T key, AVLTreeNode<T> left, AVLTreeNode<T> right) {            this.key = key;            this.left = left;            this.right = right;            this.height = -1;//定义空树的深度为-1        }    }    public AVLTree() {        root = null;    }    /**     * 新建AVL树,或者插入节点->就是new 一个新的节点 然后放置合适的位置进而调节平衡树     */    private AVLTreeNode<T> insert(AVLTreeNode<T> tree, T key) {        if (tree == null) {            //新建树//            System.out.println("新建AVLTree!");            tree = new AVLTreeNode<>(key, null, null);            if (tree == null) {                System.out.println("创建AVLTree 失败");                return null;            }        } else {            //插入节点            int temp = key.compareTo(tree.key);            //temp < 0 ,插入左节点 ;> 0 右节点 ;=0 不添加            if (temp < 0) {                tree.left = insert(tree.left, key);                if (height(tree.left) - height(tree.right) == 2) {//失衡                    if (key.compareTo(tree.left.key) < 0)                        tree = leftleftRotation(tree);                    else                        tree = leftrightRatotion(tree);                }            } else if (temp == 0) {                System.out.println("节点相同，不添加");            } else {//  >0                tree.right = insert(tree.right, key);                if (height(tree.right) - height(tree.left) == 2) {                    if (key.compareTo(tree.right.key) > 0)                        tree = rightrightRotation(tree);                    else                        tree = rightleftRaration(tree);                }            }        }        tree.height = max(height(tree.left), height(tree.right)) + 1;        return tree;    }    public void insert(T key) {        root = insert(root, key);    }    /**     * 删除节点     */    private AVLTreeNode<T> delete(AVLTreeNode<T> tree, AVLTreeNode<T> delteTree) {        if (tree == null || delteTree == null) {            return null;        }        int temp = delteTree.key.compareTo(tree.key);        if (temp < 0) {//delteTree 在根节点的左侧            tree.left = delete(tree.left, delteTree);            if (height(tree.right) - height(tree.left) == 2) {                if (height(tree.right.left) > height(tree.right.right)) {                    tree = rightleftRaration(tree);                } else {                    tree = rightrightRotation(tree);                }            }        } else if (temp > 0) {            tree.right = delete(tree.right, delteTree);            if (height(tree.left) - height(tree.right) == 2)                if (height(tree.left.left) > height(tree.left.right))                    tree = leftleftRotation(tree);                else                    tree = leftrightRatotion(tree);        } else {//删除的key            if (tree.left != null && tree.right != null) {                if (height(tree.left) > height(tree.right)) {                    AVLTreeNode<T> maxTree = maxKey(tree.left);                    tree.key = maxTree.key;                    tree.left = delete(tree.left, maxTree);                } else {                    AVLTreeNode<T> minTree = minKey(tree.right);                    tree.key = minTree.key;                    tree.right = delete(tree.right, minTree);                }            } else {                AVLTreeNode<T> tmp = tree;                tree = (tree.left != null) ? tree.left : tree.right;                tmp = null;            }        }        return tree;    }    public void delete(T key) {        AVLTreeNode<T> tree;        if ((tree = search(root, key)) != null)            root = delete(root, tree);    }    //打印二叉树    private void printAVLTree(AVLTreeNode<T> tree, T key, int direction) {        if (tree != null) {            if (direction == 0) {                System.out.printf("%2d is root\n", tree.key, key);            } else                System.out.printf("%2d is %2d's %6s child\n", tree.key, key, direction == 1 ? "right" : "left");            printAVLTree(tree.left, tree.key, -1);            printAVLTree(tree.right, tree.key, 1);        }    }    public void printAVLTree() {        if (root != null)            printAVLTree(root, root.key, 0);    }    //查找节点    private AVLTreeNode<T> search(AVLTreeNode<T> tree, T key) {        if (tree == null)            return null;        int temp = key.compareTo(tree.key);        if (temp < 0) {            return search(tree.left, key);        } else if (temp > 0) {            return search(tree.right, key);        } else            return tree;    }    public AVLTreeNode<T> search(T key) {        return search(root, key);    }    //查找AVL最小的节点    private AVLTreeNode<T> minKey(AVLTreeNode<T> tree) {        if (tree == null)            return null;        while (tree.left != null)            tree = tree.left;        return tree;    }    public T minKey() {        AVLTreeNode<T> treeNode = minKey(root);        if (treeNode != null) {            return treeNode.key;        }        return null;    }    //查找AVL 最大的节点    private AVLTreeNode<T> maxKey(AVLTreeNode<T> tree) {        if (tree == null)            return null;        while (tree.right != null)            tree = tree.right;        return tree;    }    public T maxKey() {        AVLTreeNode<T> treeNode = maxKey(root);        if (treeNode != null) {            return treeNode.key;        }        return null;    }    //Tree height    private int height(AVLTreeNode<T> tree) {        if (tree != null) {            return tree.height;        }        return -1;    }    public int height() {        return height(root);    }    //比较大小 计算高度    public int max(int a, int b) {        return a > b ? a : b;    }    //LL 旋转 k->发生失衡的节点  返回值k1->根节点    private AVLTreeNode<T> leftleftRotation(AVLTreeNode<T> k) {        AVLTreeNode<T> k1;        k1 = k.left;        k.left = k1.right;        k1.right = k;        k.height = max(height(k.left), height(k.right)) + 1;        k1.height = max(height(k1.left), k.height) + 1;        return k1;    }    //RR 旋转    private AVLTreeNode<T> rightrightRotation(AVLTreeNode<T> k) {        AVLTreeNode<T> k1;        k1 = k.right;        k.right = k1.left;        k1.left = k;        k.height = max(height(k.left), height(k.right)) + 1;        k1.height = max(height(k1.right), k.height) + 1;        return k1;    }    //LR旋转    private AVLTreeNode<T> leftrightRatotion(AVLTreeNode<T> k) {        AVLTreeNode<T> k1;        k.left = rightrightRotation(k.left);        k1 = leftleftRotation(k);        return k1;    }    //RL旋转    private AVLTreeNode<T> rightleftRaration(AVLTreeNode<T> k) {        AVLTreeNode<T> k1;        k.right = leftleftRotation(k.right);        k1 = rightrightRotation(k);        return k1;    }    private static int arr[] = {3, 2, 1, 4, 5, 6, 7, 16, 15, 14, 13, 12, 11, 10, 8, 9};//,    public static void main(String[] args) {        int i;        AVLTree<Integer> tree = new AVLTree<Integer>();        System.out.printf("== 依次添加: ");        for (i = 0; i < arr.length; i++) {            System.out.printf("%d ", arr[i]);            tree.insert(arr[i]);        }        System.out.printf("== 高度: %d\n", tree.height());        tree.printAVLTree();        tree.delete(11);//        tree.printAVLTree();    }}
阅读全文
1 0