Created
June 9, 2024 21:32
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Browser History, leetcode solution
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class History: | |
def __init__(self, url, prev=None, next_node=None): | |
self.url = url | |
self.prev = prev | |
self.next = next_node | |
class BrowserHistory: | |
def __init__(self, homepage: str): | |
self.head = History(homepage) | |
# time O(1) | |
# space O(1) | |
def visit(self, url: str) -> None: | |
new_page = History(url) | |
new_page.prev = self.head | |
self.head.next = new_page | |
self.head = self.head.next | |
# time O(n) | |
# space O(1) | |
def back(self, steps: int) -> str: | |
while steps and self.head.prev: | |
self.head = self.head.prev | |
steps -= 1 | |
return self.head.url | |
# time O(n) | |
# space O(1) | |
def forward(self, steps: int) -> str: | |
while steps and self.head.next: | |
self.head = self.head.next | |
steps -= 1 | |
return self.head.url |
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