RosettaCodeData/Task/Non-continuous-subsequences/PascalABC.NET/non-continuous-subsequences...

30 lines
914 B
ObjectPascal

function AllSubSets<T>(a: List<T>; i: integer; lst: List<T>): sequence of List<T>;
begin
if i = a.Count then yield lst
else
begin
lst.Add(a[i]);
yield sequence AllSubSets(a, i + 1, lst);
lst.RemoveAt(lst.Count - 1);
yield sequence AllSubSets(a, i + 1, lst);
end;
end;
function IsContinuous(lst: List<integer>) :=
if lst.Count > 0 then lst[^1] - lst[0] + 1 = lst.Count else true;
function ncsub<T>(seq: list<T>) :=
Allsubsets(Lst(1..seq.Count), 0, new List<integer>)
.Where(s -> not iscontinuous(s))
.Select(s -> s.Select(i -> seq[i - 1]).ToList);
begin
var seq := |'C', 'D', 'A', 'E', 'B'|.ToList;
println('Non-continuous subsequences for', seq, ':');
ncsub(seq).Println;
println;
println('Non-continuous subsequences:');
for var n := 1 to 20 do
println([1..n], '=', ncsub([1..n].ToList).Count);
end.