PHP sorting algorithm? PHP sorting classic algorithm_PHP tutorial

$count = count($arr);

for($i=0; $i<$count; $i++){

for($j=$i+1; $j<$count; $j++){

 /**
* Four sorting algorithm designs (PHP)
*
* 1) The basic idea of ​​​​Insertion Sort is:
Each time a record to be sorted is inserted into the appropriate position in the previously sorted sub-file according to its key size, until all records are inserted.
2) The basic idea of ​​Selection Sort is:
In each pass, the record with the smallest keyword is selected from the records to be sorted, and the order is placed at the end of the sorted sub-file until all records are sorted.
3) The basic idea of ​​bubble sorting is:
Compare the keywords of the records to be sorted pairwise. If it is found that the order of the two records is reversed, they will be exchanged until there are no records in the reverse order.
4) Quick sort is essentially the same as bubble sort, and is an application of exchange sort. So the basic idea is the same as the bubble sort above.
*
* @author quanshuidingdang
​*/
class Sort {
 private $arr  = array(); 
 private $sort = 'insert';
 private $marker = '_sort';
 
 private $debug = TRUE;
 
 /**
* Constructor
*
* @param array For example: $config = array (
            'arr' => array(22,3,41,18), //Array values ​​that need to be sorted
'Sort' = & gt; 'insert', // Possibly value: Insert, Select, Bubble, Quick
           'debug' => TRUE                                                                                                                                                                                                                           . )
​*/
 public function __construct($config = array()) {
  if ( count($config) > 0) {
   $this->_init($config);
  }
 }
 
 /**
* Get sorted results
​*/
 public function display() {
  return $this->arr;
 }
 
 /**
* Initialization
*
* @param array
* @return bool
​*/
 private function _init($config = array()) {
  //参数判断
  if ( !is_array($config) OR count($config) == 0) {
   if ($this->debug === TRUE) {
    $this->_log("sort_init_param_invaild");
   }
   return FALSE;
  }
  
  //初始化成员变量
  foreach ($config as $key => $val) {
   if ( isset($this->$key)) {
    $this->$key = $val;
   }
  }
  
  //调用相应的成员方法完成排序
  $method = $this->sort . $this->marker;
  if ( ! method_exists($this, $method)) {
   if ($this->debug === TRUE) {
    $this->_log("sort_method_invaild");
   }
   return FALSE;
  }
  
  if ( FALSE === ($this->arr = $this->$method($this->arr)))
   return FALSE;
  return TRUE;
 }
 
 /**
* Insertion sort
*
* @param array
* @return bool
​*/
 private function insert_sort($arr) {
  //参数判断
  if ( ! is_array($arr) OR count($arr) == 0) {
   if ($this->debug === TRUE) {
    $this->_log("sort_array(insert)_invaild");
   }
   return FALSE;
  }
  
  //具体实现
  $count = count($arr);
  for ($i = 1; $i < $count; $i++) {
   $tmp = $arr[$i];
   for($j = $i-1; $j >= 0; $j--) { 
    if($arr[$j] > $tmp) {
     $arr[$j+1] = $arr[$j];
     $arr[$j] = $tmp;
    }
   }
  }
  return $arr;
 }
 
 /**
*Select sort
*
* @param array
* @return bool
​*/
 private function select_sort($arr) {
  //参数判断
  if ( ! is_array($arr) OR count($arr) == 0) {
   if ($this->debug === TRUE) {
    $this->_log("sort_array(select)_invaild");
   }
   return FALSE;
  }
  
  //具体实现
  $count = count($arr);
  for ($i = 0; $i < $count-1; $i++) {
   $min = $i;
   for ($j = $i+1; $j < $count; $j++) {
    if ($arr[$min] > $arr[$j])  $min = $j;
   }
   if ($min != $i) {
    $tmp = $arr[$min];
    $arr[$min] = $arr[$i];
    $arr[$i] = $tmp;
   }
  }
  return $arr;
 }
 
 /**
* Bubble sort
*
* @param array
* @return bool
​*/
 private function bubble_sort($arr) {
  //参数判断
  if ( ! is_array($arr) OR count($arr) == 0) {
   if ($this->debug === TRUE) {
    $this->_log("sort_array(bubble)_invaild");
   }
   return FALSE;
  }
  
  //具体实现
  $count = count($arr);
  for ($i = 0; $i < $count; $i++) {
   for ($j = $count-1; $j > $i; $j--) {
    if ($arr[$j] < $arr[$j-1]) {
     $tmp = $arr[$j];
     $arr[$j] = $arr[$j-1];
     $arr[$j-1] = $tmp;
    }
   }
  }
  return $arr; 
 }
 
 /**
* Quick sort
*
* @param array
* @return bool
​*/
 private function quick_sort($arr) {
  //具体实现
  if (count($arr) <= 1) return $arr;
  $key = $arr[0];
  $left_arr = array();
  $right_arr = array();
  for ($i = 1; $i < count($arr); $i++){
   if ($arr[$i] <= $key)
    $left_arr[] = $arr[$i];
   else
    $right_arr[] = $arr[$i];
  }
  $left_arr = $this->quick_sort($left_arr);
  $right_arr = $this->quick_sort($right_arr);

  return array_merge($left_arr, array($key), $right_arr);
 }
 
 /**
* Logging
​*/
 private function _log($msg) {
  $msg = 'date[' . date('Y-m-d H:i:s') . '] ' . $msg . 'n';
  return @file_put_contents('sort_err.log', $msg, FILE_APPEND);
 }
}

/*End of file sort.php*/
/*Location htdocs/sort.php */