RosettaCodeData/Task/Proper-divisors/Prolog/proper-divisors-1.pro
2023-07-01 13:44:08 -04:00

48 lines
968 B
Prolog

divisor(N, Divisor) :-
UpperBound is round(sqrt(N)),
between(1, UpperBound, D),
0 is N mod D,
(
Divisor = D
;
LargerDivisor is N/D,
LargerDivisor =\= D,
Divisor = LargerDivisor
).
proper_divisor(N, D) :-
divisor(N, D),
D =\= N.
%% Task 1
%
proper_divisors(N, Ds) :-
setof(D, proper_divisor(N, D), Ds).
%% Task 2
%
show_proper_divisors_of_range(Low, High) :-
findall( N:Ds,
( between(Low, High, N),
proper_divisors(N, Ds) ),
Results ),
maplist(writeln, Results).
%% Task 3
%
proper_divisor_count(N, Count) :-
proper_divisors(N, Ds),
length(Ds, Count).
find_most_proper_divisors_in_range(Low, High, Result) :-
aggregate_all( max(Count, N),
( between(Low, High, N),
proper_divisor_count(N, Count) ),
max(MaxCount, Num) ),
Result = (num(Num)-divisor_count(MaxCount)).