MaxDoubleSliceSum Demo Task at Codility.com

Codility.com Tests 100/100 Solutions

Lesson 7 – Maximum slice problem – MaxDoubleSliceSum demo task solution code written in php. Gives 100/100 score at the time of publishing.

The description of the problem is copyrighted, so please see the following link for it:  https://codility.com/demo/take-sample-test/max_double_slice_sum

Solution in php:

function solution($A) {
    $i = $n = 0;
    $n = count($A);

    if(3 == $n){
        return 0;
    }

    $max_sum_end   = array_fill(0, $n, 0);
    $max_sum_start = array_fill(0, $n, 0);

    for($i = 1; $i < ($n - 1); $i++){
        $max_sum_end[$i] = max(0, $max_sum_end[$i - 1] + $A[$i]);
    }

    for($i = $n - 2; $i > 0; $i--){
        $max_sum_start[$i] = max(0, $max_sum_start[$i + 1] + $A[$i]);
    }

    $temp     = $maxvalue = 0;

    for($i = 1; $i < ($n - 1); $i++){
        $temp = $max_sum_end[$i - 1] + $max_sum_start[$i + 1];
        if($temp > $maxvalue){
            $maxvalue = $temp;
        }
    }

    return $maxvalue;
}

Given “AS IS”, can be ported from other languages from solutions found on the internet, please use with care.

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