构建乘积数组

import java.util.ArrayList;
public class Solution {
    public int[] multiply(int[] A) {
        int size=A.length;
        if(size==0||A==null){
            return null;
        }
        int[] res=new int[size];
        res[0]=1;
        for(int i=1;i<size;++i){
            res[i]=res[i-1]*A[i-1];
        }
        int tmp=1;
        for(int i=size-2;i>=0;--i){
            tmp*=A[i+1];
            res[i]*=tmp;
        }
        return res;
    }
}