65 lines
1.5 KiB
OCaml
65 lines
1.5 KiB
OCaml
type elem = int32
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let badRand (seed : elem) : elem = Int32.add (Int32.mul seed 1664525l) 1013904223l
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let mkRandomArray (seed : elem) n =
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let s = ref seed in
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Array.init n (fun _ ->
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let seed = !s in
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s := badRand seed;
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seed)
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exception Unsorted of string
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let rec checkSortedAux (a : elem array) i =
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if i < Array.length a - 1 then begin
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if a.(i) > a.(i+1) then raise (Unsorted "array is not sorted");
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checkSortedAux a (i+1)
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end
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let swap (arr : elem array) i j =
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let x = arr.(i) in
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let y = arr.(j) in
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arr.(i) <- y;
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arr.(j) <- x
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let rec partitionAux hi pivot arr i j : int =
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if j < hi then
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if arr.(j) < pivot then begin
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swap arr i j;
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partitionAux hi pivot arr (i+1) (j+1)
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end else
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partitionAux hi pivot arr i (j+1)
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else begin
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swap arr i hi;
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i
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end
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let partition arr lo hi =
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let mid = (lo + hi) / 2 in
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if arr.(mid) < arr.(lo) then swap arr lo mid;
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if arr.(hi) < arr.(lo) then swap arr lo hi ;
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if arr.(mid) < arr.(hi) then swap arr mid hi;
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let pivot = arr.(hi) in
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partitionAux hi pivot arr lo lo
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let rec qsortAux arr low high =
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if low < high then
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let mid = partition arr low high in
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qsortAux arr low mid;
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qsortAux arr (mid+1) high
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else ()
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let qsort arr =
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qsortAux arr 0 (Array.length arr - 1)
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let main n =
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for _ = 0 to n-1 do
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for i = 0 to n-1 do
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let xs = mkRandomArray (Int32.of_int i) i in
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qsort xs;
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checkSortedAux xs 0
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done
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done;;
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main (int_of_string Sys.argv.(1))
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