Product of Array Elements Except Self in PHP

function productArray($arr, $n)

{

    // Base case

    if ($n == 1) {

        echo "0";

        return;

    }



    $left = [];

    $right = [];

    $prod = [];



    $left[0] = 1;

    $right[$n - 1] = 1;



    // Construct the left array

    for ($i = 1; $i < $n; $i++)

        $left[$i] = $arr[$i - 1] * $left[$i - 1];



    // Construct the right array

    for ($j = $n - 2; $j >= 0; $j--)

        $right[$j] = $arr[$j + 1] * $right[$j + 1];



    // Construct the product array

    // using left[] and right[]

    for ($i = 0; $i < $n; $i++)

        $prod[$i] = $left[$i] * $right[$i];



    // print the constructed prod array

    for ($i = 0; $i < $n; $i++)

        echo $prod[$i], " ";



    return;

}



// Driver Code

$arr = [2, 3, 5, 4, 6];

$n = count($arr);

echo "The product array is : \n";

productArray($arr, $n);

function productExceptSelf($nums) {

    // Determine the length of the input list 'nums'.

    $num_length = count($nums);



    // Initialize the answer list with 1's of the same length as 'nums'.

    $answer = array_fill(0, $num_length, 1);



    // 'left' will represent the cumulative product of elements to the left of the current element.

    $left = 1;

    for ($i = 0; $i < $num_length; $i++) {

        // Store the cumulative product in the 'answer' list at the current index 'i'.

        $answer[$i] = $left;

        // Update 'left' to include the product of the current element.

        $left *= $nums[$i];

    }



    // 'right' will represent the cumulative product of elements to the right of the current element.

    $right = 1;

    for ($i = $num_length - 1; $i >= 0; $i--) {

        // Multiply the existing value in 'answer' by the 'right' value which is the product of elements to the right of 'i'.

        $answer[$i] *= $right;

        // Update 'right' to include the product of the current element.

        $right *= $nums[$i];

    }



    // Return the 'answer' list which now contains the products except self.

    return $answer;

}



print_r(productExceptSelf([2, 3, 4, 5]));