Leetcode 238: Product of Array Except Self

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

Solve it without division and in O(n).

For example, given [1,2,3,4], return [24,12,8,6].

Follow up:
Could you solve it with constant space complexity? (Note: The output array does not count as extra space for the purpose of space complexity analysis.)

 

public class Solution {
    public int[] ProductExceptSelf(int[] nums) {
        int len = nums.Length;
        int[] result = new int[len];
        
        int left = 1;
        for (int i = 0; i < len; i++)
        {
            result[i] = i == 0 ? left : nums[i - 1] * left;
            left = result[i];
        }
        
        int right = 1;
        for (int i = len - 1; i >= 0; i--)
        {
            result[i] = right * result[i];
            right *= nums[i];
        }
        
        return result;
    }
}