main =>
  L = [9,8,7,6,5,0,1,2,3,4],
  Len = L.len,
  println([select(L,1,Len,I) : I in 1..Len]),
  nl.

select(List, Left, Right, K) = Select =>
  if Left = Right then
    Select = List[Left]
  else
    PivotIndex  = partition(List, Left, Right, random(Left,Right)),
    if K == PivotIndex then
      Select = List[K]
    elseif K < PivotIndex then
      Select = select(List, Left, PivotIndex-1, K)
    else
      Select = select(List, PivotIndex+1, Right, K)
    end
  end.

partition(List, Left, Right, PivotIndex) = StoreIndex =>
  PivotValue = List[PivotIndex],
  swap(List,PivotIndex,Right),
  StoreIndex = Left,
  foreach(I in Left..Right-1)
    if List[I] @< PivotValue then
      swap(List,StoreIndex,I),
      StoreIndex := StoreIndex+1
    end
  end,
  swap(List,Right,StoreIndex).

% swap L[I] <=> L[J]
swap(L,I,J) =>
  T = L[I],
  L[I] := L[J],
  L[J] := T.