LeetCode---Generate Parentheses

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

For example, given n = 3, a solution set is:

"((()))", "(()())", "(())()", "()(())", "()()()"

解决方案：

public class Solution {    public void unguarded_generate(List<String> result,String curr,int m,int n){        if(m==0&&n==0){            result.add(curr);        }        else        {            if(m!=0){                unguarded_generate(result,curr+"(",m-1,n);            }            if(m<n&&n!=0){                unguarded_generate(result,curr+")",m,n-1);            }        }            }            public List<String> generateParenthesis(int n) {        List<String> result=new ArrayList<String>();        if(n>0){            unguarded_generate(result,new String(),n,n);        }        return result;    }}