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:
[ "((()))", "(()())", "(())()", "()(())", "()()()" ]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | class Solution {public: vector<string> generateParenthesis(int n) { vector<string> res; dfs(res,"",n,0); return res; } void dfs(vector<string> &res, string str, int l, int r){ if(l == 0 && r ==0){ res.push_back(str); return; } if(l > 0) dfs(res, str+‘(‘, l - 1, r + 1); if(r > 0) dfs(res, str+‘)‘, l, r - 1); }}; |
原文：http://www.cnblogs.com/zhxshseu/p/a44db0600fe2adbb31aa501a69be6cec.html