Solution: Longest Valid Parentheses
Explore how to identify the longest valid substring of parentheses by applying the stack pattern. Understand how the stack tracks unmatched indexes, enabling you to calculate valid segment lengths in a single pass. This lesson helps you implement and analyze an efficient solution for matching parentheses challenges.
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We'll cover the following...
Statement
You are given a string composed entirely of ‘(’ and ‘)’ characters. Your goal is to identify the longest contiguous segment (substring) within this string that represents a “well-formed” or “valid” sequence of parentheses.
A substring is considered valid if:
Every opening parenthesis ‘
(’ has a corresponding closing parenthesis ‘)’.The pairs of parentheses are correctly nested.
Return the length of this longest valid substring.
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