238. Product of Array Except Self
Array, Prefix Sum, AMateList, Prefix/Suffix ·Problem Statement
link: https://leetcode.com/problems/product-of-array-except-self/ https://leetcode.cn/problems/product-of-array-except-self/
Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i].
The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
You must write an algorithm that runs in O(n) time and without using the division operation.
Example:
Input: nums = [1,2,3,4]
Output: [24,12,8,6]
Input: nums = [-1,1,0,-3,3]
Output: [0,0,9,0,0]
Solution Approach
Algorithm
Implement
class Solution:
def productExceptSelf(self, nums: List[int]) -> List[int]:
l = len(nums)
res = [1] * l
for i in range(1, l):
res[i] = res[i - 1] * nums[i - 1]
productR = 1
for i in range(l-1, -1, -1):
res[i] *= productR
productR *= nums[i]
return res