字典树

字典树

高效存储查找字符串【以空间换时间】

模板

可以维护许多信息：

①某个字符串出现的次数；

②判断前后缀；

class node:
    def __init__(self):
        self.son = dict()

    def insert(self,s):
        cur = self
        for i in s:
            if i not in cur.son:
                cur.son[i] = node()
            cur = cur.son[i]
                    
    def search(self,s):
        cur = self
        for i in s:
            if i not in cur.son:
                break
            cur = cur.son[i]