Question

My requirement is to find the greatest/max value in an array, which may contain other arrays within it. For example we could have a look at an array below.

$array =
    array(
        13,
        array(10, 4, 111, 3),
        4,
        array(23, 450, 12,array(110, 119, 20, 670), 45 ,45,67,89),
        );

$max = find_max($array, 0);

print "Maximumum Value is  $max";

I already have a working function find_max, but all I wanted to know is what could the best and efficient possible way to do this other than the code given below.

function find_max($array, $maxValue) {
    foreach ($array as $member) {
        if (is_array($member)) {
            $maxValue = find_max($member, $maxValue);
        } else {

            if($member==$maxValue){
                continue;
            }
            if ($member > $maxValue) {
                $maxValue = $member;
            }
        }
    }
    return $maxValue;
}

Answer 1

Finding the max value requires O(n), so you can’t improve it drastically, as far as I know.
But, you can add a minor improvement to your code:

function find_max($array, $maxValue) {
    foreach ($array as $member) {
        if (is_array($member)) {
            $maxValue = find_max($member, $maxValue);
        } else {
            if ($member > $maxValue) {
                $maxValue = $member;
            }
        }
    }
    return $maxValue;
}

$array =
array(
    13,
    array(10, 4, 111, 3),
    4,
    array(23, 450, 12,array(110, 119, 20, 670), 45 ,45,67,89),
    );
$ans = find_max($array, 0);
echo "ans = $ans";

output: 670