Learn how to implement insertion sort in PHP with examples

/**
 * Insertion sort
 * @param Array $a unordered set
 * @return Array ordered set
*/
function insertSort($a) {
 $temp;
 $i;
 $j;
 $size_a = count($ a);
 #Start from the second element
 for ($i = 1; $i < $size_a; $i++) {
if ($a[$i] < $a[$i-1]) {
 $j = $i; # Save the position of the current element
 $temp = $a[$i]; # The value of the current element

 # Compare the element on the left, if it finds one smaller than itself, move the element to the right , otherwise insert the element to the current position
 while($j>0 && $temp<$a[$j-1]) {
$a[$j] = $a[$j-1];
$j-- ;
 }
 # Insert element
 $a[$j] = $temp;
}
 }
 return $a;
}
/**
 * Get random number
 * @param Integer $size quantity
 * @return Integer
*/
function randomNumber ($size = 10) {
 $rand = array();
 srand(time(NULL));
 for ($i = 0; $i < $size; $i++) {
array_push($rand, mt_rand (0,1000));
 }
 return $rand;
}

$a = randomNumber();
echo sprintf("Unsorted list %sn", implode(" ", $a));
echo sprintf( "Sorted list %sn", implode(" ", insertSort($a)));

php insertion sort implementation code

Insertion sort: Insert a piece of data into the sorted sorted data to obtain a new sorted data with the number plus one.

Algorithm description: ⒈ Starting from the first element, the element can be considered to have been sorted ⒉ Take out the next element and scan from back to front in the sorted element sequence ⒊ If the element (sorted) is larger than the new element, move the element to the next position ⒋ Repeat step 3 until you find the position where the sorted element is less than or equal to the new element ⒌ Insert the new element into the next position ⒍ Repeat step 2

Example:

$arr =array(123,0,5,-1,4,15);
function insertSort(&$arr){
//default first A number with a subscript of 0 is an arranged number
for($i=1;$i//Determine the number for insertion and comparison
$insertVal=$arr[$ i];
//Confirm and compare with the previously compared number
$insertIndex=$i-1;
//Indicates that the position is not found
while($insertIndex>=0 && $insertVal< $arr[$insertIndex]){
//Move the number back
$arr[$insertIndex+1]=$arr[$insertIndex];
$insertIndex--;
}
//Insert (find the position for $insertval )
$arr[$insertIndex+1] = $insertVal;
}
}
insertSort($arr);
print_r($arr);
?>