Balanced Parentheses Checker

StackString

Given a string containing only the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. A string is considered valid if brackets open and close correctly in the correct order. For example, '()' and '()[]{}' are valid, but '(]' and '([)]' are not.

Example 1

Input

[
  "()"
]

Output

true

Explanation. Simple pair of parentheses, which are correctly formatted.

Example 2

Input

[
  "()[]{}"
]

Output

true

Explanation. Multiple types of brackets, all correctly formatted and closed.

Example 3

Input

[
  "(]"
]

Output

false

Explanation. The parentheses are closed in the incorrect order.

Example 4

Input

[
  "([)]"
]

Output

false

Explanation. The brackets are not closed in the correct nested order.

Example 5

Input

[
  "{[]}"
]

Output

true

Explanation. All types of brackets are used and each is properly nested and closed.

Follow-up: Can you extend your solution to include other types of brackets or different characters?

Constraints:

The input string will only contain the characters '(', ')', '{', '}', '[' and ']'.

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