PHP Common sorting algorithm

Sorting algorithms

<?phpnamespace iphp\algorithm;/** * Created by PhpStorm. * User:  123 * date: 14-9-3 * time:  pm 3:53 */class sort{     /**     *  bubble sort      *  algorithm, 2 adjacent elements compared, if the former is greater than the latter, Swap position      *  First comparison, the largest element is ranked at the end.      *  need n-1 times bubble      *  @param   $arr       *  @return  mixed     */    public  static function bubble ($arr)     {          $num =count ($arr)         if ($num <=1)              return  $arr;         //Some logos are used to judge if there is no exchange at one time. Then there is no need for the next cycle &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBsp;  $flag =false;        for ($i =0; $i < $num-1; $i + +)          {           for ($j = 0 $j < $num $i $j + +)            {                //Exchange Elements                 if ($arr [$j]> $arr [$j +1])                 {                     $tmp = $arr [$j];                     $arr [$j]= $arr [$j +1];                      $arr [$j +1]= $tmp;                     $flag =true;                }           }            if ($flag ==false)                 break;        }         return  $arr;    }    /**      *  Select Sort      *  First, take the minimum value between each 1-n element, compare it to the No. 0 element, and put the smallest one in front.      *  @param   $arr      *  @return  mixed      */    public static function select ($arr)     {         $num =count ($arr);         if ($num <= 1)             return  $arr;         for ($i =0; $i < $num-1; $i + +)         {              $minValue = $arr [$i];              $minIndex = $i;             for ($j = $i +1; $j < $num; $j + +)              {                 if ($minValue > $arr [$j])                  {                      $minValue = $arr [$j];                      $minIndex = $j;                 }             }            //Swap Location              if ($i! = $j)              {                  $tmp = $arr [$i];                  $arr [$i]= $minValue;                  $arr [$minIndex]= $tmp;             }        }        return  $arr;     }    /**     *  Insert Sort       *  initially treats the first element of the array as a sorted array. The subsequent elements are compared with the ordered, inserted into the sorted position.      *  @param   $arr      *  @return  mixed      */    public static function insert ($arr)     {         $num =count ($arr);         if ($num <=1)              return  $arr,         for ($i =1; $i < $num; $i +)          {            $ Insertvalue= $arr [$i];&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBsp;    $insertIndex = $i -1;             while ($insertIndex >=0 &&  $insertValue < $arr [$insertIndex])              {                  $arr [$insertIndex +1]= $arr [$insertIndex];                  $insertIndex--;             }              $arr [$insertIndex +1]= $insertValue;        }         return  $arr;     }    /* *     *  Quick Sort      *  @param   $arr       *  @return   Array     */    public static function quick ($arr )     {         $num =count ($arr);         if ($num <=1)              return  $arr;         $middle = $arr [0];          $leftArr =array ();         $rightArr =array ();         for ($i =1; $i < $num; $i + +)          {            if ($arr [$i]<=$ Middle)                 $ leftarr[]= $arr [$i];            else                  $RIGHTARR []= $arr [$i];         }         $leftArr =self::quick ($LEFTARR);          $rightArr =self::quick ($RIGHTARR);         return array_merge ($LEFTARR, Array ($middle), $RIGHTARR);     }}

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PHP Common sorting algorithm