Product of Array Except Self LeetCode

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

Example:

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

NOTE: Please solve it without division and in O(n).

Follow up:

• Could you solve it with constant space complexity? (The output array does not count as extra space for the purpose of space complexity analysis.)
• Solve without using division and analyze the runtime and space complexity. Example: given the array [2,  7,  3,  4], your function would return: [84, 24, 56, 42],   (by calculating: [7*3*4, 2*3*4, 2*7*4, 2*7*3])

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Solution: