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bug in rating sort function solved
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@TamaroWalter
TamaroWalter committed Jan 18, 2024
1 parent 164e3f6 commit 787f5e0
Showing 1 changed file with 60 additions and 42 deletions.
102 changes: 60 additions & 42 deletions classes/ratings.php
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Original file line number Diff line number Diff line change
Expand Up @@ -226,18 +226,17 @@ public static function moodleoverflow_get_reputation($moodleoverflowid, $userid
}

/**
* Sort the answers of a discussion by their marks and votes.
* Sort the answers of a discussion by their marks, votes and for equal votes by time modified.
*
* @param array $posts all the posts from a discussion.
*/
public static function moodleoverflow_sort_answers_by_ratings($posts) {

// Create a copy that only has the answer posts and save the parent post.
$answerposts = $posts;
$parentpost = array_shift($answerposts);

// Create an empty array for the sorted posts and add the parent post.
$sortedposts = array();
$sortedposts = [];
$sortedposts[0] = $parentpost;

// Check if solved posts are preferred over helpful posts.
Expand Down Expand Up @@ -268,7 +267,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
$startsolved = $index;
$starthelpful = $index;
$startother = $index;
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $startsolvedandhelpful, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $startsolvedandhelpful, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $startsolvedandhelpful, $index - 1);
}

// Check if solutions are preferred.
Expand All @@ -285,7 +285,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
if ($index > $startsolved) {
$starthelpful = $index;
$startother = $index;
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $startsolved, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $startsolved, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $startsolved, $index - 1);
}

// Build the group of only helpful posts.
Expand All @@ -298,7 +299,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
// Update the indices and sort the group by votes.
if ($index > $starthelpful) {
$startother = $index;
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $starthelpful, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $starthelpful, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $starthelpful, $index - 1);
}
} else {

Expand All @@ -313,7 +315,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
if ($index > $starthelpful) {
$startsolved = $index;
$startother = $index;
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $starthelpful, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $starthelpful, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $starthelpful, $index - 1);
}

// Build the group of only solved posts.
Expand All @@ -326,7 +329,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
// Update the indices and sort the group by votes.
if ($index > $startsolved) {
$startother = $index;
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $startsolved, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $startsolved, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $startsolved, $index - 1);
}
}

Expand All @@ -339,7 +343,8 @@ public static function moodleoverflow_sort_answers_by_ratings($posts) {
}
// Update the indices and sort the group by votes.
if ($index > $startother) {
self::moodleoverflow_quicksort_post_by_votes($sortedposts, $startother, $index - 1);
self::moodleoverflow_quicksort_posts($sortedposts, $startother, $index - 1, 'votesdifference');
self::moodleoverflow_check_equal_votes($sortedposts, $startother, $index - 1);
}

// Rearrange the indices and return the sorted posts.
Expand Down Expand Up @@ -814,23 +819,38 @@ public static function moodleoverflow_user_can_rate($post, $modulecontext, $user

/**
* Sorts answerposts of a discussion with quicksort algorithm
* @param array $posts the posts that are being sorted
* @param int $low the index from where the sorting begins
* @param int $high the index until the array is being sorted
* @param array $posts the posts that are being sorted
* @param int $low the index from where the sorting begins
* @param int $high the index until the array is being sorted
* @param string $sortby the attribute by which the posts are being sorted, can be 'votesdifference' or 'modified'
*/
private static function moodleoverflow_quicksort_post_by_votes(array &$posts, $low, $high) {
private static function moodleoverflow_quicksort_posts(array &$posts, $low, $high, $sortby): void {
if ($low >= $high) {
return;
}
$left = $low;
$right = $high;
$pivot = $posts[intval(($low + $high) / 2)]->votesdifference;
$pivot = 0;
if ($sortby == 'votesdifference') {
$pivot = $posts[intval(($low + $high) / 2)]->votesdifference;
} else if ($sortby == 'modified'){
$pivot = $posts[intval(($low + $high) / 2)]->modified;
}
do {
while ($posts[$left]->votesdifference > $pivot) {
$left++;
}
while ($posts[$right]->votesdifference < $pivot) {
$right--;
if ($sortby == 'votesdifference') {
while ($posts[$left]->votesdifference > $pivot) {
$left++;
}
while ($posts[$right]->votesdifference < $pivot) {
$right--;
}
} else if ($sortby == 'modified') {
while ($posts[$left]->modified < $pivot) {
$left++;
}
while ($posts[$right]->modified > $pivot) {
$right--;
}
}
if ($left <= $right) {
$temp = $posts[$right];
Expand All @@ -841,35 +861,33 @@ private static function moodleoverflow_quicksort_post_by_votes(array &$posts, $l
}
} while ($left <= $right);
if ($low < $right) {
self::moodleoverflow_quicksort_post_by_votes($posts, $low, $right);
self::moodleoverflow_quicksort_posts($posts, $low, $right, $sortby);
}
if ($high > $left ) {
self::moodleoverflow_quicksort_post_by_votes($posts, $left, $high);
self::moodleoverflow_quicksort_posts($posts, $left, $high, $sortby);
}
}

private static function moodleoverflow_mergesort_post_by_votes(array &$posts, $low, $high): array {
$length = $high - $low;
if ($length <= 1) {
return $posts;
}
$mid = $low + (int) ($length / 2);

self::moodleoverflow_mergesort_post_by_votes($posts, $low, $mid);
self::moodleoverflow_mergesort_post_by_votes($posts, $mid + 1, $high);
return self::moodleoverflow_merge_posts($post, $low, $mid, $mid+1, $high);
}

private static function moodleoverflow_merge_posts(&$posts, $leftlow, $lefthigh, $rightlow, $righthigh) {
while ($leftlow <= $lefthigh && $rightlow <= $righthigh) {
// Sort after votesdifference, then sort after time created.
if ($posts[$leftlow]->votesdifference > $posts[$rightlow]->votesdifference) {
$leftlow++;
/**
* Helper function for moodleoverflow_sort_answer_by_rating. For posts that have the same mark and votesdifference, the posts are
* sorted by time modified
* @param array $posts The array that will be sorted
* @param int $low Startindex from where equal votes will be checked
* @param int $high Endindex until where equal votes will be checked
* @return void
*/
private static function moodleoverflow_check_equal_votes(&$posts, $low, $high) {
while ($low < $high) {
if ($posts[$low]->votesdifference == $posts[$low + 1]->votesdifference) {
$tempstartindex = $low;
$tempendindex = $tempstartindex + 1;
while (($tempendindex + 1 <= $high) && ($posts[$tempendindex]->votesdifference == $posts[$tempendindex + 1]->votesdifference)) {
$tempendindex++;
}
self::moodleoverflow_quicksort_posts($posts,$tempstartindex, $tempendindex, 'modified');
$low = $tempendindex + 1;
} else {
$value = $posts[$rightlow];
$index = $rightlow;

//Shift all the element
$low++;
}
}
}
Expand Down

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