leetcode_22_Generate Parentheses

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

在做这道题时，在字符串如何生成时，思考了许久无果，还是对数据结构没有深刻领悟，于是查了资料，发现可以类似于二叉树的做法。

如下图，借鉴于别人

代码如下

public static List<String> generateParenthesis(int n) {String s ="";List<String> list = new ArrayList<String>();leaf(list,n, n, s);return list;            }public static void leaf(List<String> list,int left,int right,String leaf){if(left == 0 && right == 0){list.add(leaf);return ;}if(left != 0){leaf(list, left - 1, right ,leaf + '(');}if(right != 0 && left < right){leaf(list, left, right - 1 ,leaf + ')');}}