【剑指offer】题52：构建乘积数组

vector<int> multiply(const vector<int>& A)
{
vector<int> re(A.size());
if (A.size()<=1)
{
return re;
}
vector<int> C(A.size(),1);
vector<int> D(A.size(),1);
for (auto i = 1; i < A.size();++i)
{
C[i] = C[i - 1] * A[i - 1];
}
for (int i = A.size()-2; i >= 0;--i)//auto -> unsigned int
{
D[i] = D[i + 1] * A[i + 1];
}
for (auto i = 0; i < A.size();++i)
{
re[i] = C[i] * D[i];
}
return re;
}