构建乘积数组

题目描述
给定一个数组A[0,1,...,n-1],请构建一个数组B[0,1,...,n-1],其中B中的元素B[i]=A[0]A[1]...A[i-1]A[i+1]...A[n-1]。不能使用除法。

python solution:

# -*- coding:utf-8 -*-
class Solution:
    def multiply(self, A):
        length = len(A)
        B = [0 for i in range(length)]
        if length!=0:
            B[0] = 1
            #计算下三角的结果
            for i in range(1,length):
                B[i] = B[i-1]*A[i-1]
            temp = 1
            #计算上三角的结果
            for j in range(length-2,-1,-1):
                temp *= A[j+1]
                B[j] *= temp
        return B