构建乘积数组

 1 class Solution {
 2 public:
 3     vector<int> multiply(const vector<int>& A) {
 4         vector<int> result,result1,result2;
 5         if (A.size() == 0)
 6             return result;
 7         if(A.size() == 1)
 8         {
 9             result.push_back(0);
10             return result;
11         }
12         result1.push_back(1);
13         int len = A.size();
14         for(int i = 1 ;i < len ;++i)
15         {
16             result1.push_back(result1[i-1]*A[i-1]);
17         }
18         for(int i = 0 ;i < len ;++i)
19         {
20             result2.push_back(1);
21         }
22         for(int i = len - 2 ;i >= 0 ; --i)
23         {
24             result2[i] = result2[i+1]*A[i+1];
25         }
26         for(int i = 0 ;i < len ;++i)
27         {
28             result.push_back(result1[i]*result2[i]);
29         }
30         return result;
31     }
32 };