blog-static/code/cs325-langs/sols/hw1.lang

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