February-22.java

//{ Driver Code Starts
// Initial Template for Java

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String args[]) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(in.readLine());
        while (t-- > 0) {
            String S = in.readLine();

            Solution ob = new Solution();
            System.out.println(ob.maxLength(S));

            System.out.println("~");
        }
    }
}
// } Driver Code Ends

class Solution {
    static int maxLength(String s) {
        int l = 0, r = 0, m = 0;
        for (char c : s.toCharArray()) {
            if (c == '(') l++;
            else r++;
            if (l == r) m = Math.max(m, 2 * r);
            else if (r > l) l = r = 0;
        }
        l = r = 0;
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == '(') l++;
            else r++;
            if (l == r) m = Math.max(m, 2 * l);
            else if (l > r) l = r = 0;
        }
        return m;
    }
}



2)
class Solution {
    static int maxLength(String s) {
        java.util.Stack<Integer> st = new java.util.Stack<>();
        st.push(-1);
        int m = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == '(') st.push(i);
            else {
                st.pop();
                if (st.empty()) st.push(i);
                else m = Math.max(m, i - st.peek());
            }
        }
        return m;
    }
}