Quickselect[ds : DataStructure["DynamicArray", _], k_] := QuickselectWorker[ds, 1, ds["Length"], k];
QuickselectWorker[ds_, low0_, high0_, k_] := Module[{pivotIdx, low = low0, high = high0},
   While[True,
    If[low === high,
     Return[ds["Part", low]]
     ];
    pivotIdx = SelectPartition[ds, low, high];
    Which[k === pivotIdx,
     Return[ds["Part", k]],
     k < pivotIdx,
     high = pivotIdx - 1,
     True,
     low = pivotIdx + 1
     ]
    ]
   ];
SelectPartition[ds_, low_, high_] := Module[{pivot = ds["Part", high], i = low, j},
   Do[
    If[ds["Part", j] <= pivot,
     ds["SwapPart", i, j];
     i = i + 1
     ]
    ,
    {j, low, high - 1}
    ];
   ds["SwapPart", i, high];
   i
   ];
ds = CreateDataStructure["DynamicArray", {9, 8, 7, 6, 5, 0, 1, 2, 3, 4}];
Quickselect[ds, #] & /@ Range[10]