Description：
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:
"((()))", "(()())", "(())()", "()(())", "()()()"
参考：http://blog.csdn.net/yutianzuijin/article/details/13161721
public class Solution { public void solve(int left, int right, String ans, List<String> res) { if(left == 0 && right == 0) { res.add(ans); } if(left > 0) { solve(left-1, right, ans+"(", res); } if(right>0 && left<right) { solve(left, right-1, ans+")", res); } } public List<String> generateParenthesis(int n) { List<String> list = new ArrayList<String>(); String ans = new String(); solve(n, n, ans, list); return list; } }
LeetCode——Generate Parentheses
原文：http://www.cnblogs.com/wxisme/p/4870407.html