题目
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:
[
"((()))",
"(()())",
"(())()",
"()(())",
"()()()"
]
频度： 4
解题之法
class Solution {
public:
vector<string> generateParenthesis(int n) {
vector<string> res;
addingpar(res, "", n, 0);
return res;
}
void addingpar(vector<string> &v, string str, int n, int m){
if(n==0 && m==0) {
v.push_back(str);
return;
}
if(m > 0){ addingpar(v, str+")", n, m-1); }
if(n > 0){ addingpar(v, str+"(", n-1, m+1); }
}
};
