iframe-proxy | Sunbelt Computer Software

20 lines (19 loc) · 556 Bytes

"""

Given a string containing just the characters

'(', ')', '{', '}', '[' and ']',

determine if the input string is valid.

The brackets must close in the correct order,

"()" and "()[]{}" are all valid but "(]" and "([)]" are not.

"""

def is_valid(s: str) -> bool:

stack = []

dic = {")": "(",

"}": "{",

"]": "["}

for char in s:

if char in dic.values():

stack.append(char)

elif char in dic:

if not stack or dic[char] != stack.pop():

return False

return not stack

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