[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:

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

Solution:

public class Solution {
    public List<String> generateParenthesis(int n) {
        List<String> result=new ArrayList<String>(); 
        dfs(n,n,result,"");  
        return result;
    }

    private void dfs(int left, int right, List<String> result, String temp) {
        // TODO Auto-generated method stub
        if(right<0||left<0)
            return;
        if(right==0&&left==0)
            result.add(temp);
        if(left>0)
            dfs(left-1, right, result, temp+"(");
        if(right>left)
            dfs(left, right-1, result, temp+")");
    }
}