PHP Solution
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```php []
class Solution {

    /**
     * @param Integer[] $arr1
     * @param Integer[] $arr2
     * @return Integer[]
     */
    function addNegabinary($arr1, $arr2) {
        
        $res = [];
        $i = count($arr1) - 1;
        $j = count($arr2) - 1;
        $carry = 0;

        while ( $i >= 0 || $j >= 0 || $carry != 0)
        {
            $sum = $carry;
            $carry = 0;

            if ($i >= 0)
            {
                $sum += $arr1[$i];
            }
            if ($j >= 0)
            {
                $sum += $arr2[$j];
            }
            if ($sum === 2)
            {
                $sum = 0;
                $carry = -1;
            }    
            if ($sum >= 3)
            {
                $sum = 1;
                $carry = -1;
            }
            if ($sum < 0)
            {
                $sum = 1;
                $carry = 1;
            }
            $res[] = $sum;   
            $i--;
            $j--;
        }

        $res = array_reverse($res);
        $k = 0;
        while ($res[$k] === 0 && $k < count($res) - 1)
        {
            array_shift($res);
        }

        if (   $arr1[0] === 0 
            && $arr2[0] === 0 
            && count($arr1) === 1 
            && count($arr2) === 1)
        {
            return [0];
        }
        return $res;
    }
}
```
['PHP']