思路

对于A中第i位，设置两个指针j1 = i - 1，j2 = i + 1. 让两个指针同时往两侧走，直到两侧都到达边界为止，将乘积压入B.

C++ 代码

class Solution {
public:
    vector<int> multiply(const vector<int>& A) {
        vector<int> B;
        for(int i = 0; i < A.size();i++)
        {  int j1 = i - 1, j2 = i + 1;
           int res = 1;
           while(j1 >= 0 || j2 < A.size())
           {
               if(j1 >= 0) res = res*A[j1];
               if(j2 < A.size()) res = res*A[j2];
               j1--;
               j2++;
           }
           B.push_back(res); 
        }
        return B;
    }
};