How to make Triangle Roll-Up with PHP?

Question

I found a question on google like this :

When given the input : 4, 7, 3, 6, 7

The output like this :

81

40 41

21 19 22

11 10 9 13

4  7          


        

Answer 1

 0) {
        foreach ($input as $k=>$v) {
            if (isset($input[$k+1]))
                $line[] = $v + $input[$k+1];
        }
        $return = implode(' ', $input);
        rollup($line);
    }
    if (!empty($return))
        echo $return . '
';
}

?>