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[] res = new int[nums.length];        for (int i = 0, tmp = 1; i < nums.length; i++) {            res[i] = tmp;            tmp *= nums[i];        }        for (int i = nums.length-1, tmp = 1; i >= 0; i--) {            res[i] *= tmp;            tmp *= nums[i];        }        return res;    }}