get extremes from list of numbers [closed]

Answer 1

I didn't test this much, and it won't really work with anything with fewer than 3 point, but this should give you a good starting point.

 $curr && $curr < $array[$i + 1]) {
        $extremes[] = $curr;
    }
    //maxes
    else if ($last < $curr && $curr > $array[$i + 1]) {
        $extremes[] = $curr;
    }
    if($last != $curr && $curr != $array[$i + 1]) {
        $last = $curr;
    }
}
//add last point
$extremes[] = $array[$num - 1];

print_r($extremes);

Gives you the results (you missed a couple in your list):

Array
(
    [0] => 10
    [1] => 8
    [2] => 9
    [3] => 4
    [4] => 11
    [5] => 10
    [6] => 30
    [7] => 28
    [8] => 29
    [9] => 1
)

If you want to make it be exactly like you're list, you'll have to apply some smoothing to the data, or some tolerances to the detection.