Parenthese.java

import java.util.LinkedList;

class Parenthese {
    public static int longestValidParentheses(String s) {
        int s_length = s.length();
        int d[] = new int[s_length];
        LinkedList<Integer> stack = new LinkedList<>();
        int index = 0;
        int max = 0;
        for(int i=0;i<s_length;i++){
            if(s.charAt(i)=='('){
                stack.push(i);
            }else{
                if(stack.isEmpty()){
                    index = i+1;
                }else{
                    int cur = stack.pop();
                    if(stack.isEmpty()){
                        max = Math.max(max, i-index+1);
                    }else{
                        max = Math.max(max,i-stack.peek()+1);
                    }
                }
            }
        }
        return max;
    }
    public static void main(String[] args) {
        // System.out.println("test");
        System.out.println(longestValidParentheses(")()())"));
    }
}