题解一(python): 1classSolution:2defisValid(self, s: str) ->bool:3dic = {')':'(',']':'[','}':'{'}#字典4stack =[]5foriins:6ifstackandiindic:#若栈不为空且i为有效字符串7ifstack[-1] == dic[i]:#若栈顶元素能和dic[i]匹配,则出栈8stack.pop()9else:10returnFalse#否则就...
Python3解leetcode Valid Parentheses 问题描述: Given a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in th...
代码(Python3) class Solution: def longestValidParentheses(self, s: str) -> int: # ans 表示当前最长合法括号子串的长度,初始化为 0 ans: int = 0 # stack 存储当前未匹配的 '(' 和 ')' 的下标, # 为了方便处理,初始放入 -1 ,表示有一个未匹配的 ')' stack: List[int] = [-1] # 带下标...
必须和新进来的右括号进行匹配,负责就是非法字符串## 这是一个比较巧妙的方法,先在栈底部加入一个元素,以解决空字符串的问题classSolution(object):defisValid(self,s):""":type s: str 字符串类型:rtype: bool 返回布尔型"""stack=['A']## 栈底加入了 A 字符m={')':'(',']':'[','...
Python代码: Python代码我没有使用判读左括号和右括号距离的方法 代码语言:javascript 代码运行次数:0 运行 AI代码解释 class Solution: # @return a boolean def isValid(self, s): length = len(s) stack = [] if length % 2 != 0: return False for i in range(length): if s[i] == ')' or...
assert Solution().isValid("(((") == False 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 欢迎查看我的Github(https:///gavinfish/LeetCode-Python) 来获得相关源代码。
Python代码: Python代码我没有使用判读左括号和右括号距离的方法 class Solution: # @return a boolean def isValid(self, s): length = len(s) stack = [] if length % 2 != 0: return False for i in range(length): if s[i] == ')' or s[i] == ']' or s[i] == '}': ...
Python Code:class Solution: def longestValidParentheses(self, s: str) -> int: if not s: return 0 res = 0 stack = [-1] for i in range(len(s)): if s[i] == "(": stack.append(i) else: stack.pop() if not stack: stack.append(i) ...
https://shenjie1993.gitbooks.io/leetcode-python/032%20Longest%20Valid%20Parentheses.html 采用了动态规划,dp[i]表示以i为子字符串末尾时的最大长度,最后的结果就是dp中的最大值。如果不是空字符串,则dp[0]=0,因为一个括号肯定无法正确匹配。递推关系是: 代码语言:javascript 代码运行次数:0 运行 AI代...
20Valid ParenthesesPython1. Stack 2. Replace all parentheses with '', if empty then True 21Merge Two Sorted ListsPythonAdd a dummy head, then merge two sorted list in O(m+n) 23Merge k Sorted ListsPython1. Priority queue O(nk log k) ...