扩展AVLTree，添加克隆，合并和打印方法-extend the AVLTree class to include the following methods: clone(AVLTree<K,V> tree)；merge(AVLTree<K,V> tree1, AVLTree<K,V> tree2 )；void print(AVLTree<K, V>)

HMM模型源代码,非常适合新手使用，理解模型原理，若有问题欢迎咨询本人，一起学习学习！-HMM Model source ，very suitable for beginners to use！