Plain text compare with XML data pattern

Sample my XML data in answer_scheme.xml :

<?xml version="1.0" encoding="UTF-8"?>
<QAML_POSSIBILITY>
    <MAIN_PATTERN>
        <PATTERN_BODY_PART>
            <SEQUENCE>
                <TEXT>pointer</TEXT>
                <CONDITION>
                    <NO_WORD></NO_WORD>
                </CONDITION>
                <TEXT>array</TEXT>
            </SEQUENCE>
            <MARKS>1</MARKS>
        </PATTERN_BODY_PART>
        <PATTERN_BODY_PART>
            <SEQUENCE>
                <TEXT>array pointer</TEXT>
            </SEQUENCE>
            <MARKS>1</MARKS>
        </PATTERN_BODY_PART>
    </MAIN_PATTERN>
</QAML_POSSIBILITY>

---

A string in process_marking.php :

//Let say I got a variable of $input_answer
$input_answer = " array of pointer.";

$filter_1     = trim($input_answer);
$filter_2     = rtrim(".",$filter_1);
$filter_3     = rtrim(" ".$filter_2);

$arr_input_answer = explode(" ",$filter_3);

//Output 
$arr_input_answer = array(
         [0] => array
         [1] => of
         [2] => pointer
      )

---

Now, how I can convert my $arr_input_answer array become XML structure as above? Is it possible?

My requirement:

Actually I need to match the pattern for $arr_input_answer array with answer_scheme.xml pattern.

Is it possible to convert from that $arr_input_answer array to answer_scheme.xml?

But the things I received only a string like array of pointer. How
to achieve that requirement? Any ideas millions of thanks!