not ac 22. Generate Parentheses

class Solution {public:    vector<string> generateParenthesis(int n) {        vector<string> parentheses;        if(n==0) return parentheses;        if(n==1)         {            parentheses.push_back("()");            return parentheses;        }        int *d=new int[n];        for(int i=0;i<n;i++) d[i]=n-1;        int k=0;        int floor=n-1;        while(floor!=-1)        {            if(k>=floor) k=0;            string s(n,'(');            for(int i=0;i<n;i++)                s.insert(d[i]+i+1,")");            parentheses.push_back(s);            d[k]--;            k++;            if(d[k]==k)             {                floor--;            }        }        return parentheses;    }};