# -*- coding: utf-8 -*-

"""

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 the correct order.

Note that an empty string is also considered valid.

Example 1:

Input: "()"

Output: true

Example 2:

Input: "()[]{}"

Output: true

Example 3:

Input: "(]"

Output: false

Example 4:

Input: "([)]"

Output: false

Example 5:

Input: "{[]}"

Output: true

"""

class Solution:

def isValid(self, s):

"""

:type s: str

:rtype: bool

>>> s = Solution()

>>> s.isValid("()[]{}")

True

>>> s.isValid("()")

True

>>> s.isValid("(]")

False

>>> s.isValid("([)]")

False

>>> s.isValid("{[]}")

True

"""

stack = []

character_map = {"(": ")", "{": "}", "[": "]"}

for i in s:

if not stack:

stack.append(i)

else:

if character_map.get(stack[-1]) == i:

stack.pop()

else:

stack.append(i)

return not len(stack)

if __name__ == '__main__':

import doctest

doctest.testmod(verbose=True)