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Valid Parentheses

EasyStrings & Parsing

Given a string s containing just the characters '(', ')', '{', '}', '[', and ']', determine if the input string is valid.

An input string is valid if:

  • Open brackets are closed by the same type of brackets
  • Open brackets are closed in the correct order

Example:

Input:
()[]{}
Output:
True
Reasoning:
  • The input string ()[]{} is processed from left to right, with each opening bracket being pushed onto a stack.
  • When a closing bracket is encountered, the top of the stack is checked to ensure it contains the corresponding opening bracket: ( matches ), { matches }, and [ matches ].
  • The string is valid if the stack is empty at the end, meaning all brackets were properly closed: () is closed, [] is closed, and {} is closed.
  • Since all brackets in the input string are properly closed in the correct order, the output is True.

Constraints:

  • 1 <= len(s) <= 10^4
  • s consists of parentheses only
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Test Results

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