<?php
$input = file('input', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
$input = explode(',', $input[0]);

$minFuelCost = INF;
foreach (range(min($input), max($input)) as $newPosition) {
    $fuelCost = array_sum(array_map(fn($currentPosition) => (abs($currentPosition - $newPosition) * (abs($currentPosition - $newPosition) + 1)) / 2, $input));

    if ($fuelCost < $minFuelCost) {
        $minFuelCost = $fuelCost;
    }
}
echo $minFuelCost; //91257582