Summary of implementation of various sorting algorithms in PHP

// Bubble sort
function BubbleSort($arr) {
 // Get the total length of the array
 $num = count($arr);
 // Forward Traverse the array
 for ($i = 1; $i < $num; $i++) {
 // Reverse traverse
 for ($j = $num - 1; $j >= $i ; $j-- ) {
 // Compare two adjacent numbers
 if ($arr[$j] < $arr[$j-1]) {
 // Temporarily store the smaller number
 $iTemp = $arr[$j -1];
 // Put the bigger ones in front
 $arr[$j-1] = $arr[$j];
 // Put the smaller ones in the back
 $arr[$j] = $iTemp;
 }
 }
 }
 return $arr;
}
// Exchange sorting
function ExchangeSort($arr){
 $num = count($arr);
 // Traverse the array
 for ($i = 0;$i < $num - 1; $i++) {
 // Get the next index of the current index
 for ($j = $i + 1; $j < $num; $ j++) {
 // Compare two adjacent values ​​​​
 if ($arr[$j] < $arr[$i]) {
 // Temporarily store the smaller number
 $iTemp = $arr[$ i];
 // Put the bigger ones in front
 $arr[$i] = $arr[$j];
 // Put the smaller ones in the back
 $arr[$j] = $iTemp;
 }
 }
 } // bbs.it-home.org
 return $arr;
}
// Selection sorting
function SelectSort($arr) {
 // Get the total length of the array
 $ num = count($arr);
 // Traverse the array
 for ($i = 0;$i < $num-1; $i++) {
 // Temporarily store the current value
 $iTemp = $arr[$i ];
 // Temporarily store the current position
 $iPos = $i;
 // Traverse the data after the current position
 for ($j = $i + 1;$j < $num; $j++){
 // If there is a value smaller than the current value
 if ($arr[$j] < $iTemp) {
 // Temporary minimum value
 $iTemp = $arr[$j];
 // Temporary position
 $iPos = $ j;
 }
 }
 // Put the current value into the calculated position
 $arr[$iPos] = $arr[$i];
 // Change the current value into the calculated value
 $arr[$ i] = $iTemp;
 }
 return $arr;
}
// Insertion sorting
function InsertSort($arr){
 $num = count($arr);
 / / Traverse the array
 for ($i = 1;$i < $num; $i++) {
 // Get the current value
 $iTemp = $arr[$i];
 // Get the previous position of the current value
 $iPos = $i - 1;
 // If the current value is less than the previous value, it has not reached the beginning of the array
 while (($iPos >= 0) && ($iTemp < $arr[$iPos])) {
 // Put the previous value one digit back
 $arr[$iPos + 1] = $arr[$iPos];
 // Decrement the position
 $iPos--;
 }
 $arr[$iPos+ 1] = $iTemp;
 }
 return $arr;
}
// Quick sort
function QuickSort($arr){
 $num = count($arr);
 $l = $r = 0;
 // Traverse the array starting from the second index
 for ($i = 1;$i < $num; $i++) {
 // If the value is less than index 1
 if ($arr [$i] < $arr[0]) {
 // Load the left index array (data less than index 1)
 $left[] = $arr[$i];
 $l++;
 } else { / /bbs.it-home.org
 // Otherwise, load into the right index (data greater than index 1)
 $right[] = $arr[$i];
 $r++; //
 }
 }
 // If the left index has a value, sort the left index
 if($l > 1) {
 $left = QuickSort($left);
 }
 // Sorted array
 $new_arr = $left;
 // Will The current array is put first at the end
 $new_arr[] = $arr[0];
 // If the index has a value, sort the right index
 if ($r > 1) {
 $right = QuickSort($ right);
 }
 // Add data again according to the length of the right index
 for($i = 0;$i < $r; $i++) {
 $new_arr[] = $right[$i];
 }
 return $new_arr;
}
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