[Solved] 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].

Question

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 1:

Input: nums = [1,2,3,4]
Output: [24,12,8,6]

Example 2:

Input: nums = [-1,1,0,-3,3]
Output: [0,0,9,0,0]

Constraints:

  • 2 <= nums.length <= 105
  • -30 <= nums[i] <= 30
  • The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.

Follow up: Can you solve the problem in O(1) extra space complexity? (The output array does not count as extra space for space complexity analysis.)

Python Solution

class Solution:
    def productExceptSelf(self, nums: List[int]) -> List[int]:
        p = 1
        n = len(nums)
        out = []
        for i in range(n):
            out.append(p)
            p = p*nums[i]
        print(out)
        p=1
        for i in range(n-1,-1,-1):
            out[i] = out[i]*p
            p = p*nums[i]
        return(out)
Abhishek Sharma
Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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