34 lines
679 B
ObjectPascal
34 lines
679 B
ObjectPascal
type
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colors = (red, white, blue);
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procedure threeWayPartition(a: array of colors; mid: colors);
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begin
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var (i, j) := (0, 0);
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var k := a.High;
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while j <= k do
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if a[j] < mid then
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begin
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swap(a[i], a[j]);
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i += 1;
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j += 1;
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end
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else if a[j] > mid then
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begin
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swap(a[j], a[k]);
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k -= 1;
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end
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else j += 1;
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end;
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begin
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var balls: array of colors;
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repeat
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balls := ArrGen(10, i -> |red, white, blue|.randomelement);
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until balls <> balls.Sorted;
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println('Original ball order:', balls);
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threewaypartition(balls, white);
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println('Sorted ball order: ', balls);
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assert(balls <> balls.sorted, 'Not sorted!');
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end.
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