DSA problem
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. This rules out the obvious approach of computing the total product and dividing by each element, which also fails when the array contains zeros.
Examples
Example 1
Input:
nums = [1,2,3,4]Output:
[24,12,8,6]Explanation: answer[0] = 2*3*4 = 24, answer[1] = 1*3*4 = 12, answer[2] = 1*2*4 = 8, answer[3] = 1*2*3 = 6.
Example 2
Input:
nums = [-1,1,0,-3,3]Output:
[0,0,9,0,0]Explanation: Every position except index 2 includes the zero in its product, so only answer[2] is non-zero.
Constraints
- 2 <= nums.length <= 10^5
- -30 <= nums[i] <= 30
- The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
3 hints and a full solution walkthrough with step-by-step visualizations are available in the practice editor.