LeetCode OJ：Generate Parentheses（括号生成）

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:

"((()))", "(()())", "(())()", "()(())", "()()()"

求出所有可能的括号组合，在dfs加上回溯条件，右括号数目不能超过左括号，还有就是左括号数最大不能超过n，代码如下：

 class Solution {
 public:
     vector<string> generateParenthesis(int n) {
         dfs(,n*,,,"");
         return ret;
     }

     void dfs(int dep, int maxDep, int left, int leftTotal, string curr){
         if(leftTotal* > maxDep)
             return;
         if(dep == maxDep){
             ret.push_back(curr);
             return;
         }
         for(int i = ; i < ; i++){
             if(i == ){
                 dfs(dep+, maxDep, left+, leftTotal+, curr+"(");
             }else{
                 if(left)
                     dfs(dep+, maxDep, left-, leftTotal, curr+")");
             }
         }
     }
 private:
     vector<string> ret;
 };