PHP Decode

<?php 
function mergeSort($arr) { 
    $length = count($arr); 
     
    if ($length <= 1) { 
        return $arr; 
    } 
     
    $mid = (int) ($length / 2); 
    $left = array_slice($arr, 0, $mid); 
    $right = array_slice($arr, $mid); 
     
    $left = mergeSort($left); 
    $right = mergeSort($right); 
     
    return merge($left, $right); 
} 
 
function merge($left, $right) { 
    $result = []; 
    $leftLength = count($left); 
    $rightLength = count($right); 
    $leftIndex = $rightIndex = 0; 
     
    while ($leftIndex < $leftLength && $rightIndex < $rightLength) { 
        if ($left[$leftIndex] < $right[$rightIndex]) { 
            $result[] = $left[$leftIndex]; 
            $leftIndex++; 
        } else { 
            $result[] = $right[$rightIndex]; 
            $rightIndex++; 
        } 
    } 
     
    while ($leftIndex < $leftLength) { 
        $result[] = $left[$leftIndex]; 
        $leftIndex++; 
    } 
     
    while ($rightIndex < $rightLength) { 
        $result[] = $right[$rightIndex]; 
        $rightIndex++; 
    } 
     
    return $result; 
} 
 
// Contoh penggunaan 
$unsortedArray = [38, 27, 43, 3, 9, 82, 10]; 
$sortedArray = mergeSort($unsortedArray); 
 
echo "Array sebelum diurutkan: " . implode(", ", $unsortedArray) . "
"; 
echo "Array setelah diurutkan: " . implode(", ", $sortedArray) . "
"; 
 ?>