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package body Quick is
procedure Swap(A, B : in out Element_T) is
Temp : Element_T;
begin
Temp := A;
A := B;
B := Temp;
end Swap;
procedure In_Place(Arr : in out Array_T) is
Pivot, Left, Right : Index_T;
begin
if Arr'Length <= 1 then
return;
end if;
Pivot := Arr'First;
Left := Index_T'Succ(Pivot);
Right := Arr'Last;
loop
while not (Arr(Left) > Arr(Pivot)) and Left < Arr'Last loop
Left := Index_T'Succ(Left);
end loop;
while Arr(Right) > Arr(Pivot) and Right > Arr'First loop
Right := Index_T'Pred(Right);
end loop;
exit when Left >= Right;
Swap(Arr(Left), Arr(Right));
end loop;
Swap(Arr(Pivot), Arr(Right));
if Right > Arr'First then
In_Place( Arr(Arr'First .. Index_T'Pred(Right)) );
end if;
if Right < Arr'Last then
In_Place( Arr(Index_T'Succ(Right) .. Arr'Last) );
end if;
end In_Place;
end Quick;
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