24thJune(II).java

import java.util.List;
import java.util.ArrayList;

public class GeneratePraa {
    static List<String> generateParenthesis(int n) {
        List<String> ans = new ArrayList<>();
        helper(ans, "", 0, 0, n);
        return ans;
    }
    static void helper(List<String> ans, String currentBracket, int open , int close, int max){
        if(currentBracket.length()==max*2){
            ans.add(currentBracket);
            return;
        }
        if(open<max){
            helper(ans,currentBracket+ "(", open+1, close, max);
        }
        if(close<open){
            helper(ans,currentBracket+ ")", open, close+1, max);
        }
    }
    public static void main(String[] args) {
        System.out.println(generateParenthesis(3));
    }
}


// OP ---
// [((())), (()()), (())(), ()(()), ()()()]