#32
Longest Valid Parentheses
hard · verified · 38.2% accepted · 13,266 likes · top 17%
string · dynamic programming · stack
Description
Given a string containing just the characters '(' and ')', return the length of the longest valid (well-formed) parentheses substring.
Example 1:
Input: s = "(()"
Output: 2
Explanation: The longest valid parentheses substring is "()".
Example 2:
Input: s = ")()())"
Output: 4
Explanation: The longest valid parentheses substring is "()()".
Example 3:
Input: s = ""
Output: 0
Solution