MediumArraysFree practice
Product of Array Except Self
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01 · Problem
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.
02 · Examples
Example 01
Input
nums = [1,2,3,4]
Output
[24,12,8,6]
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 02
Input
nums = [-1,1,0,-3,3]
Output
[0,0,9,0,0]
Because there is a zero in the array at index 2, most products will be 0. answer[2] = (-1)*1*(-3)*3 = 9.
03 · Constraints
- 012 <= nums.length <= 105
- 02-30 <= nums[i] <= 30
- 03The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
04 · Optimal complexity
- Time
- O(n)
- Space
- O(1)
05 · Two ways to work on it
Practice it alone or rehearse it as an interview.
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