Fix bugs for comparing outputs with Wrong Answer and Presentation Error status

[hzxie]

As I mentioned in Issue #79, There's a bug in comparing outputs.
And here's the pull request to fix it.

Because when you compare the outputs, you stopped when reach the end of output of test case. And you didn't check if the rest of the stdout of user's program.

If there's some non-blank characters, the judge status should be Wrong Answer, but in the old code, the status would be Presentation Error.

Feel free to ask me questions and thanks for reviewing my PR.

[hzxie]

Here's the code to help you review the PR.
The following code is copied from the file judgelib.php:

<?php

// trim tailing return chars which are meaning less
$output = rtrim("100 = 2 * 2 * 5 * 5", "\r\n");
$stdout = rtrim("100 = 2 * 2 * 5 * 5 * 1\n", "\r\n");

echo diff($output, $stdout);

function diff($output, $stdout) {
    if (strcmp($output, $stdout) == 0)
        return "ONLINEJUDGE_STATUS_ACCEPTED\n";
    else {
        $tokens = array();
        $tok = strtok($output, " \n\r\t");

        while ($tok !== false) {
            $tokens[] = $tok;
            $tok = strtok(" \n\r\t");
        }
        $tok = strtok($stdout, " \n\r\t");

        // Token is output (right answer)
        foreach ($tokens as $anstok) {
            if ($tok === false || $tok !== $anstok)
                return "ONLINEJUDGE_STATUS_WRONG_ANSWER\n";
            $tok = strtok(" \n\r\t");
        }
        // The following code from line 30 to line 35 is used to fix the bug
        while ($tok !== false) {
            if ( !empty(trim($tok)) ) {
                return "ONLINEJUDGE_STATUS_WRONG_ANSWER\n";
            }
            $tok = strtok(" \n\r\t");
        }
        return "ONLINEJUDGE_STATUS_PRESENTATION_ERROR\n";
    }
}

And it's obvious that if you remove the code from 30-35, the diff() function will return the wrong status code.

[sunner]

Perhaps,

            if ($tok !== false) {
                return ONLINEJUDGE_STATUS_WRONG_ANSWER;
            } else {
                return ONLINEJUDGE_STATUS_PRESENTATION_ERROR;
            }

Is this OK?

[hzxie]

Yes, thanks for your advice @sunner.
I've updated the code. You can merge the PR directly.

[sunner]

Hi, have you tested the code with enough submissions? I can not test it now.

[hzxie]

Yes. I tested following test cases:

Test Case 1

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5\n";

Returns ONLINEJUDGE_STATUS_ACCEPTED;

Test Case 2

$output = "100 = 2 * 2 * 5 * 5\n\n";
$stdout = "100 = 2 * 2 * 5 * 5\n";

Returns ONLINEJUDGE_STATUS_ACCEPTED;

Test Case 3

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5 \n";

Returns ONLINEJUDGE_STATUS_PRESENTATION_ERROR;

Test Case 4

$output = "100 = 2 * 2 * 5 * 5 \n";
$stdout = "100 = 2 * 2 * 5 * 5\n";

Returns ONLINEJUDGE_STATUS_PRESENTATION_ERROR;

Test Case 5

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5\t\n";

Returns ONLINEJUDGE_STATUS_PRESENTATION_ERROR;

Test Case 6

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5\t \n";

Returns ONLINEJUDGE_STATUS_PRESENTATION_ERROR;

Test Case 7

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5 * 1\n";

Returns ONLINEJUDGE_STATUS_WRONG_ANSWER;

Test Case 8

$output = "100 = 2 * 2 * 5 * 5";
$stdout = "100 = 2 * 2 * 5 * 5\n * 1\n";

Returns ONLINEJUDGE_STATUS_WRONG_ANSWER;

Test Case 9

$output = "100 = 2 * 2 * 5 * 5 * 1";
$stdout = "100 = 2 * 2 * 5 * 5\n";

Returns ONLINEJUDGE_STATUS_WRONG_ANSWER;

Test Case 10

$output = "100 = 2 * 2 * 5 * 5 * 1";
$stdout = "100 = 2 * 2 * 5 * 5\t * 1\n";

Returns ONLINEJUDGE_STATUS_WRONG_ANSWER;

[sunner]

Merged. Thanks a lot!