Description

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].

Solution

使用Bi-pointer ， left记录左侧所有数字的乘积，right记录右侧所有乘积，对于每个数，只需left*right了得到结果
思路难，写简单

class Solution:
    def productExceptSelf(self, nums: List[int]) -> List[int]:
        right = left =1
        res =[1]*len(nums)
        for i in range(len(nums)):
            res[i]*=right
            res[len(nums)-1-i]*=left
            right *= nums[i]
            left *= nums[len(nums)-1-i]
        return res