本文共 857 字，大约阅读时间需要 2 分钟。

使用双向节点

class Dlinknode:    def __init__(self, page):        self.page = page        self.next = self        self.prev = selfclass BrowserHistory:    def __init__(self, homepage: str):        self.root = Dlinknode(homepage)        self.cur = self.root            def visit(self, url: str) -> None:        newpage = Dlinknode(url)        self.cur.next = newpage        newpage.prev = self.cur        self.cur = newpage    def back(self, steps: int) -> str:        for i in range(steps):            self.cur = self.cur.prev        return self.cur.page    def forward(self, steps: int) -> str:        for i in range(steps):            self.cur = self.cur.next        return self.cur.page# Your BrowserHistory object will be instantiated and called as such:# obj = BrowserHistory(homepage)# obj.visit(url)# param_2 = obj.back(steps)# param_3 = obj.forward(steps)

转载地址：http://gijii.baihongyu.com/