Sergio Alves

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.

Example 1:

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

Example 2:

Input: nums = [-1,1,0,-3,3]
Output: [0,0,9,0,0]

Constraints:

• 2 <= nums.length <= 105
• -30 <= nums[i] <= 30
• The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.

PHP Code

class Solution {

    /**
     * @param Integer[] $nums
     * @return Integer[]
     */
    function productExceptSelf($nums) {
        $product = array_product($nums);
        $output = [];

        for ($i=0; $i<count($nums); $i++) {
            if ($nums[$i] == 0) {
                $temp = $nums;
                unset($temp[$i]);
                $output[$i] = array_product($temp);
            } else {
                $output[$i] = $product * pow($nums[$i], -1);
                
            }
            if ($output[$i] == 0) {
                $output[$i] = abs($output[$i]);
            }
        }

        return $output;
    }
}