c++ leetcode generate parentheses

we can just use dfs to solve this problem.

the first terminate condition is the leftremain == rightremain == 0,and in this condition, we can just add this answer to return<vector>

and the second terminatecondition is the rightremain < leftremain.this condition would cause the parentheses not match.

we should pay attention to the place where we writh cur+"(";because of the iterate function.

cur = cur + '(' and dfs(leftremain,rightremain,cur) is a wrong statement.

we shoud write it into dfs(leftremain,rightremain,cur+'(class Solution {
public:
vector<string> ret;
void dfs(int leftremain,int rightremain,string cur)
{
if(leftremain == 0 && rightremain == 0)
{
ret.push_back(cur);
return ;
}
if(leftremain > rightremain)
return;
if(leftremain>0)
dfs(leftremain-1,rightremain,cur+'(');
if(rightremain >0)
dfs(leftremain,rightremain-1,cur+')');
}

vector<string> generateParenthesis(int n) {
dfs(n,n,"");
return ret;
}
};

')