Bubble sort implementation in PHP? [duplicate]
I need to do a bubble sort algorithm in PHP.
I want to know whether any one has any good examples that I can use, or an open source library which can do this.
I have a few spaces in a set (array), i want to fill these spaces with object (a person), so no space can have a male and a female, this why i am trying to find out a bubble sort algorithm.
My plan is to fill in any of the available spaces regardless of the gender, and after that sort them separately.
Thanks.
function bubble_sort($arr) {
$size = count($arr)-1;
for ($i=0; $i<$size; $i++) {
for ($j=0; $j<$size-$i; $j++) {
$k = $j+1;
if ($arr[$k] < $arr[$j]) {
// Swap elements at indices: $j, $k
list($arr[$j], $arr[$k]) = array($arr[$k], $arr[$j]);
}
}
}
return $arr;
}
For example:
$arr = array(1,3,2,8,5,7,4,0);
print("Before sorting");
print_r($arr);
$arr = bubble_sort($arr);
print("After sorting by using bubble sort");
print_r($arr);
Using bubble sort is a very bad idea. It has complexity of O(n^2)
.
You should use php usort, which is actually a merge sort implementation and guaranteed O(n*log(n))
complexity.
A sample code from the PHP Manual -
function cmp( $a, $b ) {
if( $a->weight == $b->weight ){ return 0 ; }
return ($a->weight < $b->weight) ? -1 : 1;
}
usort($unsortedObjectArray,'cmp');
$numbers = array(1,3,2,5,2);
$array_size = count($numbers);
echo "Numbers before sort: ";
for ( $i = 0; $i < $array_size; $i++ )
echo $numbers[$i];
echo "n";
for ( $i = 0; $i < $array_size; $i++ )
{
for ($j = 0; $j < $array_size; $j++ )
{
if ($numbers[$i] < $numbers[$j])
{
$temp = $numbers[$i];
$numbers[$i] = $numbers[$j];
$numbers[$j] = $temp;
}
}
}
echo "Numbers after sort: ";
for( $i = 0; $i < $array_size; $i++ )
echo $numbers[$i];
echo "n";
function bubble_sort($arr) {
$n = count($arr);
do {
$swapped = false;
for ($i = 0; $i < $n - 1; $i++) {
// swap when out of order
if ($arr[$i] > $arr[$i + 1]) {
$temp = $arr[$i];
$arr[$i] = $arr[$i + 1];
$arr[$i + 1] = $temp;
$swapped = true;
}
}
$n--;
}
while ($swapped);
return $arr;
}