Problem

    function solution($A);

<?php
    function solution($A)  {
        $N = count($A);

        $prevMaxSum = $A[0];
        $accumulatingMaxSum = $A[0];

        for ($i=1; $i < $N; $i++) {
            $tempRunTotal = $accumulatingMaxSum + $A[$i];  //could be smaller than A[i]
            if ($A[$i] > $tempRunTotal)
                $accumulatingMaxSum = $A[$i];  //elements start rising
            else
                $accumulatingMaxSum = $tempRunTotal;  //continue to accumulate

            if ($accumulatingMaxSum > $prevMaxSum)  //comparing all the maximum sums
                $prevMaxSum = $accumulatingMaxSum;
        }

        return $prevMaxSum;
    }

    $A = [5, -7, 3, 5, -2, 4, -1];  //  {3, 5, -2, 4} -> 10
    $ret1 = solution($A);
    echo $ret1 . "\n";

    $B = [-2, 1, -3, 4, -1, 2, 1, -5, 4];  //  {4, −1, 2, 1} -> 6
    $ret2 = solution($B);
    echo $ret2 . "\n";

    $C = [3, 2, -6, 4, 0];  //{3, 2} -> 5
    $ret3 = solution($C);
    echo $ret3 . "\n";

    $D = [3, 2, 6, -1, 4, 5, -1, 2];  //{3, 2, 6, -1, 4, 5, -1, 2} -> 20
    $ret4 = solution($D);
    echo $ret4 . "\n";

    $E = [5, 7, -4, -10, -6, 6, 5, 10, -5, 15, 4, -8, -15, -22];  // {6, 5, 10, -5, 15, 4}->35
    $ret5 = solution($E);
    echo $ret5 . "\n";

    $F = [-4, 10, 15, 9, -5, -20, -3, -12, -3, 4, 6, 3, 2, 8, 3, -5, -2];  // {10, 15, 9}->34
    $ret6 = solution($F);
    echo $ret6 . "\n";
?>