LeetCode(22)-Generate Parentheses

22. 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:
[
“((()))”,
“(()())”,
“(())()”,
“()(())”,
“()()()”
]

题目的意思是给你几组括号，然后求这括号的任意组合，开和闭必须对应
这道题不会做，看了一个大神的思路。用递归做的，开始确实比较难看懂，不过通过一步一步调试
也算懂了

public List<String> generateParenthesis(int n) {
       List<String> list = new ArrayList<String>();
       backtrack(list, "", 0, 0, n);
       return list;
   }

   public void backtrack(List<String> list, String str, int open, int close, int max){
       if(str.length() == max*2){
           list.add(str);
           return;
       }
       if(open < max)backtrack(list, str+"(", open+1, close, max);
       if(close < open)backtrack(list, str+")", open, close+1, max);
   }

不太好讲，一步一步调试就懂了