标签：
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:
"((()))", "(()())", "(())()", "()(())", "()()()"
思路：这道题要是不分析规律的话，很难想出答案本题的规律是假如left的个数大于right的个数，就可以添加‘)‘；假如left的个数小于n，就可以添加‘(‘。利用递归，先给出递归结束条件，然后不断深入。
代码：
public class Solution { public List<String> generateParenthesis(int n) { List<String> list=new ArrayList<String>(); if(n<=0)return list; generate(0, list, 2*n, "", 0, 0); System.out.println(list); return list; } public void generate(int index,List<String> list,int size,String str,int left,int right) { if(index==size) { list.add(str); return; } index++; if(left>right) generate(index, list, size, str+‘)‘, left, right+1); if(left<size/2) generate(index, list, size, str+‘(‘, left+1, right); } }
[leetcode] Generate Parentheses
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原文地址：http://www.cnblogs.com/maydow/p/4669377.html
