PHP Common sorting algorithm

Insert sort (insertion sort), choose sort (Selection sort), bubble sort and quick sort are the sort algorithms we often use. Here are the basic ideas of these algorithms and the corresponding PHP implementation code.

The basic idea of inserting a sort (insertion sort) is to insert a record to be sorted each time, by its keyword size, into the appropriate location in the previously sorted sub-file until all records are inserted.

//Insert Sort (one-dimensional array)functionInsert_sort ($arr){    $count=Count($arr);  for($i= 1;$i<$count;$i++){        $tmp=$arr[$i]; $j=$i-1;  while($arr[$j] >$tmp){            $arr[$j+1] =$arr[$j]; $arr[$j] =$tmp; $j--; }     }    return $arr;}$arr=Array(1,2,3,5,100,3,2,4,5,6,7,55,78,46);$arr=insert_sort ($arr);Print_r($arr);

The basic idea of choosing a sort (Selection sort) is that each trip selects the smallest record of the keyword from the record to be sorted, placing the order at the end of the ordered sub-file until all records have been sorted.

//Select sort (one-dimensional array)functionSelect_sort ($arr){    $count=Count($arr);  for($i= 0;$i<$count;$i++){        $k=$i;  for($j=$i+1;$j<$count;$j++){            if($arr[$k] >$arr[$j])                $k=$j; if($k!=$i){                $tmp=$arr[$i]; $arr[$i] =$arr[$k]; $arr[$k] =$tmp; }         }     }    return $arr;}$arr=Array(1,2,3,5,100,3,2,4,5,6,7,55,78,46);$arr=select_sort ($arr);Print_r($arr);

The basic idea of bubble sorting is: 22 Compare the keywords of the records to be sorted, and find that the two records are exchanged in reverse order until there are no reversed records.

//Bubble sort (one-dimensional array)functionBubble_sort ($array){    $count=Count($array); if($count<= 0)return false;  for($i= 0;$i<$count;$i++){         for($j=$count-1;$j>$i;$j--){            if($array[$j] <$array[$j-1]){                $tmp=$array[$j]; $array[$j] =$array[$j-1]; $array[$j-1] =$tmp; }         }     }    return $array;} $arr=Array(1,2,3,5,100,3,2,4,5,6,7,55,78,46);$arr=bubble_sort ($arr);Print_r($arr);

The fast sort is essentially the same as bubbling sort, which is an application that belongs to the interchange sort. So the basic idea is the same as the bubble sort above.

//Quick Sort (one-dimensional array)functionQuick_sort ($array){  if(Count($array) <= 1)return $array; $key=$array[0]; $left _arr=Array(); $right _arr=Array();  for($i= 1;$i<Count($array);$i++){    if($array[$i] <=$key)      $left _arr[] =$array[$i]; Else      $right _arr[] =$array[$i]; }  $left _arr= Quick_sort ($left _arr); $right _arr= Quick_sort ($right _arr); return Array_merge($left _arr,Array($key),$right _arr);}$arr=Array(1,2,3,5,100,3,2,4,5,6,7,55,78,46);$arr=quick_sort ($arr);Print_r($arr);