Leetcode # 20. Valid Parentheses

https://leetcode.com/problems/valid-parentheses/

Solution

Time Complexity: O(len(s))
Space Complexity: O(len(s))
(The input and output generally do not count towards the space complexity.)

class Solution:
  def isValid(self, s: str) -> bool:
    stack = []
    left_brackets  = {"(", "[", "{"}
    right_brackets = {")": "(", "]": "[", "}": "{"}
    for c in s:
      if c in left_brackets:
        stack.append(c)
      elif not stack or stack.pop() != right_brackets[c]:
        return False
    return len(stack) == 0

Last Updated on 2023/08/16 by A1go