PHP比较两个字符串并显示差异，同时保留其原始字符位置

function compareStrings($string1, $string2) {
    $length1 = strlen($string1);
    $length2 = strlen($string2);

    // 创建一个二维数组用于记录差异
    $diff = array();
    for ($i = 0; $i <= $length1; $i++) {
        $diff[$i] = array_fill(0, $length2, 0);
    }

    // 遍历字符串进行比较
    for ($i = 0; $i < $length1; $i++) {
        for ($j = 0; $j < $length2; $j++) {
            if ($string1[$i] === $string2[$j]) {
                $diff[$i+1][$j+1] = $diff[$i][$j] + 1;
            } else {
                $diff[$i+1][$j+1] = max($diff[$i+1][$j], $diff[$i][$j+1]);
            }
        }
    }

    // 提取差异并保留原始字符位置
    $result = '';
    $i = $length1;
    $j = $length2;
    while ($i > 0 && $j > 0) {
        if ($string1[$i-1] === $string2[$j-1]) {
            $result = $string1[$i-1] . $result;
            $i--;
            $j--;
        } elseif ($diff[$i][$j] === $diff[$i-1][$j]) {
            $i--;
        } else {
            $j--;
        }
    }

    return $result;
}

$string1 = "Hello, world!";
$string2 = "Hello, everyone!";
$result = compareStrings($string1, $string2);
echo $result;