Product of Array Except Self

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

Example:

Input:  [1,2,3,4]
Output: [24,12,8,6]

Constraint: It's guaranteed that the product of the elements of any prefix or suffix of the array (including the whole array) fits in a 32 bit integer.

Note: Please solve it without division and in O(n).

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

class Solution {
    // We cannot use division operator
    public int[] productExceptSelf(int[] nums) {
        int ans[] = new int[nums.length];
        int prev = 1;
        for (int i = 0; i < nums.length; i++) {
            ans[i] = prev;
            prev *= nums[i];
        }
        int next = 1;
        for (int i = nums.length - 1; i >= 0; i--) {
            ans[i] *= next;
            next *= nums[i];
        }
        return ans;
    }
}