一个简单的快速排序法

升序

  
    

   
     
   
     procedure QuickSort(var arr: array of Integer; 
   
     const
   
      left, right: Integer);

 procedure swap(
   
     const
   
      i, j: Integer);
 var
 vT: Integer;
 begin
 
   
     if
   
      i 
   
     =
   
      j then Exit;
 vT :
   
     =
   
      arr[i];
 arr[i] :
   
     =
   
      arr[j];
 arr[j] :
   
     =
   
      vT;
 end;

var
 vL, vR: Integer;
begin
 
   
     if
   
      left 
   
     >=
   
      right then Exit;
 vL :
   
     =
   
      left;
 vR :
   
     =
   
      right 
   
     +
   
      
   
     1
   
     ;
 
   
     while
   
      True 
   
     do
   
     
 begin
 
   
     while
   
      vL 
   
     +
   
      
   
     1
   
      
   
     <
   
      Length(arr) 
   
     do
   
     
 begin
 Inc(vL);
 
   
     if
   
      arr[vL] 
   
     >=
   
      arr[left] then Break;
 end;
 
   
     while
   
      vR 
   
     -
   
      
   
     1
   
      
   
     <
   
      Length(arr) 
   
     do
   
     
 begin
 Dec(vR);
 
   
     if
   
      arr[vR] 
   
     <=
   
      arr[left] then Break;
 end;
 
   
     if
   
      vL 
   
     >=
   
      vR then Break;
 swap(vL, vR);
 end;
 swap(left, vR);
 QuickSort(arr, left, vR 
   
     -
   
      
   
     1
   
     );
 QuickSort(arr, vR 
   
     +
   
      
   
     1
   
     , right);
end;

procedure TForm1.FormCreate(Sender: TObject);
var
 vA: array of Integer;
 vStr: 
   
     string
   
     ;
 i: Integer;
begin
 SetLength(vA, 
   
     10
   
     );
 vA[
   
     0
   
     ] :
   
     =
   
      
   
     41
   
     ;
 vA[
   
     1
   
     ] :
   
     =
   
      
   
     24
   
     ;
 vA[
   
     2
   
     ] :
   
     =
   
      
   
     76
   
     ;
 vA[
   
     3
   
     ] :
   
     =
   
      
   
     11
   
     ;
 vA[
   
     4
   
     ] :
   
     =
   
      
   
     45
   
     ;
 vA[
   
     5
   
     ] :
   
     =
   
      
   
     64
   
     ;
 vA[
   
     6
   
     ] :
   
     =
   
      
   
     21
   
     ;
 vA[
   
     7
   
     ] :
   
     =
   
      
   
     69
   
     ;
 vA[
   
     8
   
     ] :
   
     =
   
      
   
     19
   
     ;
 vA[
   
     9
   
     ] :
   
     =
   
      
   
     36
   
     ;
 QuickSort(vA, 
   
     0
   
     , Length(vA) 
   
     -
   
      
   
     1
   
     );
 
   
     for
   
      i :
   
     =
   
      
   
     0
   
      to Length(vA) 
   
     -
   
      
   
     1
   
      
   
     do
   
     
 vStr :
   
     =
   
      vStr 
   
     +
   
      
   
     '
   
      
   
     '
   
      
   
     +
   
      IntToStr(vA[i]);
 edt1.Text :
   
     =
   
      vStr;
end;