UNSW ProgComp: Problem 3 - 2011

<?php

//Input method, nothing fancy, deal with it.
$input = <<<END
5
15
34
79
1
200
END;

$input = explode("\n", $input); //split input into an array by new line feed (\n)
array_shift($input); //eject the first value out of the array (can be captured, but not necessary)

//Create list of optimal places to hit per each number

for($x = 1; $x < 21; $x++){
    $scores_list[$x] = "S$x";
}

for($x = 1; $x < 21; $x++){
    if(!isset($scores_list[$x*2])){
        $scores_list[$x*2] = "D$x";
    }
}

for($x = 1; $x < 21; $x++){
    if(!isset($scores_list[$x*3])){
        $scores_list[$x*3] = "T$x";
    }
}

//Insert bulls-eye scores

$scores_list[50] = 'IB';
$scores_list[25] = 'OB';

ksort($scores_list); //Sort array by array keys
$scores_list = array_reverse($scores_list, true); //Reverse the order of the elements and preserve the keys

foreach($input as $key => $value){
    //find largest number that can be taken away

    //take it away and record the new total, and the value that was taken away

    //if remainder is 0, stop. If remainder does not have a solution, take away the next largest value possible

    //loop

    $taken_away = array(); //array of the scores that are used to reach zero
    $remainder = $value; //The amount that still has to be scored
    $loop = 0; //Loop counter (similar to the counter in a for loop)
    $sum = 0; //Sum of the targets that have been hit

    while($remainder > 0 && $loop < 3){ //While there are still numbers to be taken away and three dart throws are still to be made
        foreach ($scores_list as $key => $value2) { //For each of the scores as $key and $value2
            if(($remainder - $key) >= 0) { //If the remainder, minus the target to hit, is a valid place to hit, do:
                $remainder -= $key; //Remainder = remainder - target_to_hit
                $taken_away[] = $value2; //Add the target that was hit to the array 'taken_away'
                $sum += $key; //Add the target that was hit to the sum total.
                break; //Break out of the foreach loop as it has found a value and doesn't need to search anymore
            }
        }
        $loop++; //Increase loop counter by 1
    }

    //The rest of this is just displaying the output

    echo $value.": ";
    $first = true;
    foreach($taken_away as $key => $value){
        if($first){
            echo $value.' ';
            $first = false;
        }else{
            echo '+ '.$value.' ';
        }
    }
    echo '= '.$sum."\n";
}