TIAByRange

[Janilabo]

function TIAByRange(aStart, aFinish: Integer): TIntArray;
var
 i: Integer;
begin
 if (aStart <> aFinish) then
 begin  
   SetLength(Result, (IAbs(aStart - aFinish) + 1));
   if (aStart > aFinish) then
     for i := aStart downto aFinish do
       Result[(aStart - i)] := i
   else  
     for i := aStart to aFinish do
       Result[(i - aStart)] := i;
 end else
   Result := [aStart];
end;

 

TIAByRange2bit:

 

function TIAByRange2bit(aStart, aFinish: Integer): TIntArray;
var
 g, l, i: Integer;
begin
 if (aStart <> aFinish) then
 begin 
   l := (IAbs(aStart - aFinish) + 1);             
   SetLength(Result, l);     
   g := ((l - 1) div 2);  
   case (aStart < aFinish) of
     True:
     begin
       for i := 0 to g do
       begin                       
         Result[i] := (aStart + i);
         Result[((l - 1) - i)] := (aFinish - i);
       end;
       if ((l mod 2) <> 0) then
         Result[i] := (aStart + i);   
     end;
     False:
     begin
       for i := 0 to g do
       begin                       
         Result[i] := (aStart - i);
         Result[((l - 1) - i)] := (aFinish + i);
       end;
       if ((l mod 2) <> 0) then
         Result[i] := (aStart - i);  
     end;  
   end;     
 end else
   Result := [aStart];
end;

 

Timing the methods:

TIAByRange(-999999, 999999): 1999999 items [7441 ms.]
TIAByRange2bit(-999999, 999999): 1999999 items [6942 ms.]
TIAByRange(999999, -999999): 1999999 items [7395 ms.]
TIAByRange2bit(999999, -999999): 1999999 items [7004 ms.]
Successfully executed (28784.3489 ms)

Edited September 29, 2012 by Janilabo
Functions updated.