How to print all possible balanced parentheses for an expression?

Question

For example, with elements a,b,c,d, there are 5 possible ways to take neighboring elements and reduce them into a single element, where exactly two elements mus

Answer 1

import java.util.ArrayList;


public class Parantheses {

    private ArrayList parStringList;
    private int total;

    public void exploreParantheses(String parString,int leftCnt,int rightCnt)
    {
        if (leftCnt < total)
        {
            exploreParantheses(parString + "(", leftCnt+1, rightCnt);
        }
        if ((rightCnt < total) &&(rightCnt < leftCnt))
        {
            exploreParantheses(parString + ")", leftCnt, rightCnt+1);
        }
        else if (rightCnt == total)
        {
            parStringList.add(parString);
        }
    }
    public ArrayList generateParanthesis(int numPars)
    {
        this.total = numPars;
        this.parStringList = new ArrayList();
        exploreParantheses("", 0, 0);
        return this.parStringList;
    }
    public static void main(String args[])
    {
        ArrayList par;
        par = (new Parantheses()).generateParanthesis(6);
        for (String str: par)
            System.out.println(str);
    }
}