10,11,7,6,8,9
package tree.bst.avl;
public class AVLTreeDemo {
public static void main(String[] args) {
//int[] arr = {4,3,6,5,7,8};
//int[] arr = {10,12,8,9,7,6};
int[] arr = {10,11,7,6,8,9};
AvlTree avlTree = new AvlTree();
for (int i = 0; i < arr.length; i++) {
avlTree.addNode(new Node(arr[i]));
}
// 中序遍历显示
avlTree.infixOrder();
// 求高度
System.out.println(avlTree.getRoot().height());
System.out.println(avlTree.getRoot().leftHeight());
System.out.println(avlTree.getRoot().rightHeight());
avlTree.infixOrder();
}
}
class AvlTree {
public Node getRoot() {
return root;
}
public void setRoot(Node root) {
this.root = root;
}
private Node root;
public int height()
{
if (root == null){
return 0;
} else {
return root.height();
}
}
public void addNode(Node node) {
if (root == null) {
root = node;
} else {
root.add(node);
}
}
public void infixOrder() {
if (root == null) {
return;
}
root.infixOrder();
}
public Node search(int value) {
if (root == null) {
return null;
} else {
return root.search(value);
}
}
public Node searchParent(int value) {
if (root == null) {
return null;
} else {
return root.searchParent(value);
}
}
/**
* 删除最小节点
*
* @param node 传入的节点 当做一颗二叉排序书的根节点
* @return 以node为根节点的的最小节点的值
*/
public int delRightTreeMin(Node node) {
Node temp = node;
// 循环查找左子节点找到最小值
while (temp.left != null) {
temp = temp.left;
}
// delete the mini node
deleteNode(temp.value);
return temp.value;
}
public void deleteNode(int value) {
if (root == null) {
return;
}
// find thi node
Node targetNode = this.search(value);
// 如果没有找到要删除的节点
if (targetNode == null) {
return;
}
// 没有父节点
if (root.left == null && root.right == null) {
root = null;
return;
}
Node parent = searchParent(value);
//叶子节点
if (targetNode.left == null && targetNode.right == null) {
if (parent.left != null && parent.left.value == value) {
parent.left = null;
} else if (parent.right != null && parent.right.value == value) {
parent.right = null;
}
} else if (targetNode.left != null && targetNode.right != null) { //两颗子树
int min = this.delRightTreeMin(targetNode.right);
targetNode.value = min;
} else { // 一颗子树
// if has left node
if (targetNode.left != null) {
if (parent != null) {
// 如果targetNode是parent的左右
if (parent.left.value == value) {
parent.left = targetNode.left;
} else {
parent.right = targetNode.left;
}
} else {
root = targetNode.left;
}
} else {
if (parent != null) {
if (parent.right.value == value) {
parent.right = targetNode.right;
} else {
parent.left = targetNode.right;
}
} else {
root = targetNode.right;
}
}
}
}
}
class Node {
public int value;
public Node left;
public Node right;
public Node(int value) {
this.value = value;
}
public int leftHeight() {
if (left == null) {
return 0;
} else {
return left.height();
}
}
// 左旋
private void leftRotate()
{
//创建新的结点，以当前根结点的值
Node newNode = new Node(value);
//把新的结点的左子树设置成当前结点的左子树
newNode.left = left;
//把新的结点的右子树设置成带你过去结点的右子树的左子树
newNode.right = right.left;
//把当前结点的值替换成右子结点的值
value = right.value;
//把当前结点的右子树设置成当前结点右子树的右子树
right = right.right;
//把当前结点的左子树(左子结点)设置成新的结点
left = newNode;
}
// 右旋
private void rightRotate()
{
// 10 12 8 9 7 6 拿着转了玩
Node newNode = new Node(value);
newNode.right = right;
newNode.left = left.right;
value = left.value;
left = left.left;
right = newNode;
}
public int rightHeight() {
if (right == null) {
return 0;
} else {
return right.height();
}
}
public int height() {
return Math.max(this.left == null ? 0 : this.left.height(), this.right == null ? 0 : this.right.height()) + 1;
}
// find node
public Node search(int value) {
if (value == this.value) {
return this;
} else if (value < this.value) {
// left tree find
if (this.left == null) {
return null;
}
return this.left.search(value);
} else {
if (this.right == null) {
return null;
}
return this.right.search(value);
}
}
// 查找要删除的节点的父节点
public Node searchParent(int value) {
if (this.left != null && this.left.value == value
|| (this.right != null && this.right.value == value)) {
return this;
} else {
if (value < this.value && this.left != null) {
return this.left.searchParent(value);
} else if (value >= this.value && this.right != null) {
return this.right.searchParent(value);
} else {
return null;
}
}
}
// 添加节点
public void add(Node node) {
if (node == null) {
return;
}
// 添加 left
if (node.value < this.value) {
if (this.left == null) {
this.left = node;
} else {
this.left.add(node);
}
}
// 添加到right
if (node.value > this.value) {
if (this.right == null) {
this.right = node;
} else {
this.right.add(node);
}
}
// 添加完一个节点后 如果柚子树-左子树的高度>1 左旋转
if(rightHeight() - leftHeight() > 1) {
if(right!=null && right.leftHeight() > right.rightHeight()){
right.left.rightRotate();
}
leftRotate();
} else if(leftHeight() - rightHeight() > 1) {
if(left !=null && left.rightHeight() > left.leftHeight()){
left.leftRotate();
}
rightRotate();
}
}
// 中序便利
public void infixOrder() {
if (this.left != null) {
this.left.infixOrder();
}
System.out.println(this);
if (this.right != null) {
this.right.infixOrder();
}
}
@Override
public String toString() {
return "Node{" +
"value=" + value +
'}';
}
}