import java.util.ArrayList;

import java.util.List;

/**

* Description:

* User: liqing@pluosi

* Date: 2020-11-16

* Time: 11:02 PM

*/

public class GenerateParenthesis {

private List<String> result;

public List<String> generateParenthesis(int n) {

result = new ArrayList<String>();

_generate(0,0,n,"");

return result;

}

private void _generate(int left, int right,int n, String s){

if(left==n && right == n){

result.add(s);

}

if(left<n){

_generate(left+1,right,n,s+"(");

}

if(left > right){

_generate(left,right+1,n,s+")");

}

}

public static void main(String[] args) {

System.out.println(new GenerateParenthesis().generateParenthesis(3));

}

}