Leetcode-1028 Convert to Base -2(负二进制转换)

class Solution
{
    public:
        string baseNeg2(int N)
        {
            string ss;
            int  n = N;
            stack<int> s;
            int a;
            if(n == 0)
                return "0";
            else
            {
                while(n!=0)
                {
                    a = abs(n%(-2));
                    s.push(a);
                    n = (n-a) / (-2);
                }
            }
            while(!s.empty())
            {
                ss+=s.top()+'0';
                s.pop();
            }
            return ss;
        }
};