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:
[ "((()))", "(()())", "(())()", "()(())", "()()()" ]
题目含义：给出n对括号组成的所有字符串
1 private void backTrace(List<String > list,String str,int open,int close,int max) 2 { 3 //open代表左括号目前的数量 close代表右括号目前的数量 4 if (str.length() == max*2) 5 { 6 list.add(str);return; 7 } 8 if (open<max) backTrace(list,str+"(",open+1,close,max); 9 if (close<open) backTrace(list,str+")",open,close+1,max); 10 } 11 12 public List<String> generateParenthesis(int n) { 13 List<String > list = new ArrayList<>(); 14 backTrace(list,"",0,0,n); 15 return list; 16 }
原文：http://www.cnblogs.com/wzj4858/p/7682698.html