20 lines
584 B
Plaintext
20 lines
584 B
Plaintext
qselect(xs,k) =
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~xs -> {
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pivot <- xs[0]!
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left <- xs[#0 <= pivot]
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right <- xs[#0 > pivot]
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} ->
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if k > |left| + 1 then qselect(right, k - |left| - 1)
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else if k == |left| + 1 then [pivot]
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else qselect(left, k);
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_search(xs, k) =
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if xs[1] == k then xs
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else if xs[1] > k then _search(xs[0], k)
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else _search(xs[2], k);
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sorted(xs) = sorted(xs[0]) ++ [xs[1]] ++ sorted(xs[2]);
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search(xs, k) = |_search(xs, k)| != 0;
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insert(xs, k) = _insert(k, _search(xs, k));
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_insert(k, xs) = if |xs| == 0 then xs << [] << k << [] else xs
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