[LeetCode] 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:

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

class Solution {
public:
vector<string> generateParenthesis(int n) {
vector<string> list;

stack<string> stack1 ;
stack<int> vaStack1;
stack1.push("(");
vaStack1.push(0);//存储右括号的数量

while(stack1.size()!=0){

string s = stack1.top();
int v = vaStack1.top();//v是右括号的数量
stack1.pop();
vaStack1.pop();
if(s.size()==n*2){
list.push_back(s);
continue;
}
if(s.size()-v<n){//左括号的数量小于n，给s后面补左括号
stack1.push(s+"(");
vaStack1.push(v);
}
if(2*v<s.size()){//缺右括号，给s后面补左括号
stack1.push(s+")");
vaStack1.push(v+1);
}
}
return list;
}
};