304 North Cardinal St.
Dorchester Center, MA 02124

# Longest Valid Parentheses LeetCode Solution

## Problem – Longest Valid Parentheses LeetCode Solution

Given a string containing just the characters `'('` and `')'`, find 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
``````

Constraints:

• `0 <= s.length <= 3 * 104`
• `s[i]` is `'('`, or `')'`.

## Longest Valid Parentheses LeetCode Solution in Java

``````public class Solution {
public int longestValidParentheses(String s) {
Stack<Integer> stack = new Stack<Integer>();
int max=0;
int left = -1;
for(int j=0;j<s.length();j++){
if(s.charAt(j)=='(') stack.push(j);
else {
if (stack.isEmpty()) left=j;
else{
stack.pop();
if(stack.isEmpty()) max=Math.max(max,j-left);
else max=Math.max(max,j-stack.peek());
}
}
}
return max;
}
}
``````

## Longest Valid Parentheses LeetCode Solution in C++

``````class Solution {
public:
int longestValidParentheses(string s) {
stack<int> stk;
stk.push(-1);
int maxL=0;
for(int i=0;i<s.size();i++)
{
int t=stk.top();
if(t!=-1&&s[i]==')'&&s[t]=='(')
{
stk.pop();
maxL=max(maxL,i-stk.top());
}
else
stk.push(i);
}
return maxL;
}
};
``````

## Longest Valid Parentheses LeetCode Solution in Python

``````  def longestValidParentheses(self, s):
dp, stack = *(len(s) + 1), []
for i in range(len(s)):
if s[i] == '(':
stack.append(i)
else:
if stack:
p = stack.pop()
dp[i + 1] = dp[p] + i - p + 1
return max(dp)
``````
##### Longest Valid Parentheses LeetCode Solution Review:

In our experience, we suggest you solve this Longest Valid Parentheses LeetCode Solution and gain some new skills from Professionals completely free and we assure you will be worth it.

If you are stuck anywhere between any coding problem, just visit Queslers to get the Longest Valid Parentheses LeetCode Solution

Find on Leetcode

##### Conclusion:

I hope this Longest Valid Parentheses LeetCode Solution would be useful for you to learn something new from this problem. If it helped you then don’t forget to bookmark our site for more Coding Solutions.

This Problem is intended for audiences of all experiences who are interested in learning about Data Science in a business context; there are no prerequisites.

Keep Learning!

More Coding Solutions >>

LeetCode Solutions

Hacker Rank Solutions

CodeChef Solutions