数据结构中PAT树的实现，包括树节点的插入、删除、查找和遍历。PAT tree 在字符串子串匹配上有这非常优异的表现，这使得它经常成为一种高效的全文检索算法，在自然语言处理领域也有广泛的应用。-PAT tree data structure, including the insertion of the tree node, delete, search, and traversal. PAT tree in the string substring match this excellent performance, which makes it often become an efficient search algorithm, a wide range of applications in the field of natural language processing.