class Solution {public:    vector
     
       productExceptSelf(vector
      
       & nums) {        if (nums.size() == 0)   return vector
       
        ();        vector
        
          res(nums.size(), 1);        for (int i = 1; i < nums.size(); i++) {            res[i] = res[i-1] * nums[i-1];        }        int p = 1;        for (int i = nums.size()-2; i >= 0; i--) {            p = p * nums[i+1];            res[i] = res[i] * p;        }        return res;    }};