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valid-parentheses_20.py
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valid-parentheses_20.py
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# Given a string s 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 the correct order.
# Every close bracket has a corresponding open bracket of the same type.
# Example 1:
# Input: s = "()"
# Output: true
# Example 2:
# Input: s = "()[]{}"
# Output: true
# Example 3:
# Input: s = "(]"
# Output: false
# ---------------------------------------Runtime 51 ms Beats 12.1% Memory 16.3 MB Beats 10.96%---------------------------------------
class Solution:
def isValid(self, s: str) -> bool:
brackets = {
"(": ")",
"{": "}",
"[": "]",
}
stack = [0]
for x in s:
if x in brackets:
stack.append(x)
else:
if brackets.get(stack.pop()) != x:
return False
return stack == [0]