二叉查找树(AVL)插入算法Java实现

public static class Node {

int data;

Node left;

Node right;

int height;

};

public int Height(Node p) {

if (p == null) {

return -1;

} else {

return p.height;

}

}

public Node rightRotate(Node k2) 

{ 

    Node k1; 

    k1 = k2.left; 

    k2.left = k1.right; 

    k1.right = k2; 

    k2.height = Math.max(Height(k2.left), Height(k2.right)) + 1; 

    k1.height = Math.max(Height(k1.left), k2.height) + 1; 

    return k1; 

}

public Node DoubleRightRotate(Node k3) {

k3.left = rightRotate(k3.left);

return rightRotate(k3);

}

public Node Insert(int data, Node root) {

if (root == null) {

root = new Node();

root.data = data;

root.height = 0;

root.left = root.right = null;

} else if (data < root.data) {

root.left = Insert(data, root.left);

if (Height(root.left) - Height(root.right) == 2) {

if (data < root.left.data) {

root = rightRotate(root);

} else {

root.left = rightRotate(root.left);

root = rightRotate(root);

}

}

} else if (data < root.data) {

root.right = Insert(data, root.right);

if (Height(root.right) - Height(root.left) == 2){

if (data > root.right.data) {

root = leftRotate(root);

} else {

root.left = leftRotate(root.left);

root = leftRotate(root);

}

}

}

root.height = Math.max(Height(root.left), Height(root.right)) + 1;

return root;

}