Balanced Parentheses
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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.
- An empty string is also considered valid.
Example 1
Input
[ "()" ]
Output
true
Explanation. This standard pairing is valid.
Example 2
Input
[ "()[]{}`" ]
Output
true
Explanation. All types of brackets are correctly nested and closed in the right order.
Example 3
Input
[ "(]" ]
Output
false
Explanation. The parenthesis is closed with a different type of bracket.
Example 4
Input
[ "([)]" ]
Output
false
Explanation. The brackets are not closed in the correct order.
Example 5
Input
[ "{" ]
Output
false
Explanation. The single opening brace is never closed.
Example 6
Input
[ "{[]}" ]
Output
true
Explanation. Complex nesting is valid and closed correctly.
Follow-up: Could there be any performance considerations if the function is to be run against a large dataset?
Constraints:
The length of the input string is between 0 and 10,000. You may assume the string contains only the characters listed above.
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