How should I practice Product of Array Except Self?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Capgemini phone screen problems in FastPrep.

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FastPrep tags this as a Capgemini phone screen coding practice problem when the problem catalog has that company and stage context.

Product of Array Except Self

Capgemini● MediumFULLTIMEPHONE SCREEN

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Problem statement

Given an integer array nums, return an array answer where answer[i] equals the product of every element of nums except nums[i].

Solve the problem without division in O(n) time. The output array does not count as extra space.

Function

productExceptSelf(nums: int[]) → int[]

Examples

Example 1

nums = [1,2,3,4]return = [24,12,8,6]

For index 0, the product is 2 * 3 * 4 = 24; apply the same rule at every index.

Example 2

nums = [-1,1,0,-3,3]return = [0,0,9,0,0]

Only the position containing zero has a nonzero result, equal to (-1) * 1 * (-3) * 3 = 9.

Example 3

nums = [2,3]return = [3,2]

With two values, each output is the other value.

Constraints

2 <= nums.length <= 10^5.
-30 <= nums[i] <= 30.
Every prefix product and suffix product fits in a signed 32-bit integer.