50 · 数组剔除元素后的乘积

描述
给定一个整数数组A。
定义B[i] = A[0] * ... * A[i-1] * A[i+1] * ... * A[n-1]， 计算B的时候请不要使用除法。请输出B。

样例
样例 1

输入: A = [1, 2, 3]
输出: [6, 3, 2]
解析：B[0] = A[1] * A[2] = 6; B[1] = A[0] * A[2] = 3; B[2] = A[0] * A[1] = 2
样例 2

输入: A = [2, 4, 6]
输出: [24, 12, 8]

class Solution:
    """
    @param: nums: Given an integers array A
    @return: A long long array B and B[i]= A[0] * ... * A[i-1] * A[i+1] * ... * A[n-1]
    """
    def productExcludeItself(self, nums):
        lefts = [1]*len(nums)
        rights = [1]*len(nums)
        for i in range(1,len(nums)):
            lefts[i] = lefts[i-1]*nums[i-1]
        for i in range(len(nums)-2,-1,-1):
            rights[i] = rights[i+1]*nums[i+1]
        return [lefts[i] * rights[i] for i in range(len(nums))]